U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1980 to 1999 (With short-term projections to dates in 2000) Source: Population Estimates Program, Population Division, U.S. Census Bureau Internet Release Date: April 11, 2000 TABLE OF CONTENTS I. DATA FILE DESCRIPTIONS II. DATA FILE RECORDS A. Record Layout B. Explanation of Data Fields III. POPULATION UNIVERSE AND TIME SERIES IV. THE ESTIMATES BASE POPULATION V. POSTCENSAL ESTIMATION OF RESIDENT POPULATION A. Estimation of Population By Sex, Race, and Hispanic Origin B. Estimation of Components of Population Change C. Estimation of Population By Age D. Estimation of Population By Quarter and Month I. DATA FILE DESCRIPTIONS The National Population Estimates page on the U.S. Census Bureau web site links to two series of detailed national population estimates data. One series, available as an electronic product, contains quarterly intercensal national population estimate data between April 1, 1980 and April 1, 1990. The other series, available only on the Internet, contains monthly postcensal national population estimate data for April 1, 1990 and onward. Each series contains estimate files that cover the nation (50 states plus the District of Columbia) by single year of age, sex, race, and Hispanic origin. Both series contain national estimate data for the resident, resident plus Armed Forces overseas, and civilian populations. The monthly postcensal series also provides national estimate data for the civilian noninstitutional population. The quarterly intercensal series are consistent with annual population estimates for dates from April 1, 1980, to April 1, 1990, as published in Current Population Reports, Series P-25, Number 1095, "U.S. Population Estimates, by Age, Sex, Race, and Hispanic Origin: 1980 to 1991" and on the Population Division electronic product PE-10. The monthly postcensal series does not have any corresponding paper or electronic product. Neither series of estimates are adjusted for net undercoverage found in either the 1980 or 1990 Decennial Censuses. The 1990 estimates are adjusted for census count question resolution corrections and net undercoverage found in the test sites for the 1995 test censuses. All estimates are consistent with currently published annual estimates of the population prior to 1980 by age, sex, and race, as they appear in Current Population Reports, Series P-25, Numbers 311, 519, and 917. The 1990 population estimates supersede all previous estimates for dates after April 1, 1990, as the estimates of population change since the 1990 census have been revised. These estimates are preliminary and subject to future revision. The paper and electronic products for the quarterly intercensal national population estimates between April 1, 1980 and April 1, 1990 may be purchased by writing to the Statistical Information Staff, Population Division, Bureau of the Census, Stop 8800, Washington, D.C., 20233-8800. A list of the files in each estimate series are listed below. For both the quarterly intercensal and monthly postcensal packages, the files are stored in ASCII format. NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1980 TO APRIL 1, 1990 RESIDENT POPULATION File Name File description E8081RQI.TXT Quarterly intercensal resident population estimates, April 1, 1980, to January 1, 1981 (4 reference dates, 408 records, 90,577 bytes) E8182RQI.TXT Quarterly intercensal resident population estimates, April 1, 1981, to January 1, 1982 (4 reference dates, 408 records, 90,577 bytes) E8283RQI.TXT Quarterly intercensal resident population estimates, April 1, 1982, to January 1, 1983 (4 reference dates, 408 records, 90,577 bytes) E8384RQI.TXT Quarterly intercensal resident population estimates, April 1, 1983, to January 1, 1984 (4 reference dates, 408 records, 90,577 bytes) E8485RQI.TXT Quarterly intercensal resident population estimates, April 1, 1984, to January 1, 1985 (4 reference dates, 408 records, 90,577 bytes) E8586RQI.TXT Quarterly intercensal resident population estimates, April 1, 1985, to January 1, 1986 (4 reference dates, 408 records, 90,577 bytes) E8687RQI.TXT Quarterly intercensal resident population estimates, April 1, 1986, to January 1, 1987 (4 reference dates, 408 records, 90,577 bytes) E8788RQI.TXT Quarterly intercensal resident population estimates, April 1, 1987, to January 1, 1988 (4 reference dates, 408 records, 90,577 bytes) E8889RQI.TXT Quarterly intercensal resident population estimates, April 1, 1988, to January 1, 1989 (4 reference dates, 408 records, 90,577 bytes) E8990RQI.TXT Quarterly intercensal resident population estimates, April 1, 1989, to April 1, 1990 (5 reference dates, 510 records, 113,221 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1980 TO APRIL 1, 1990 RESIDENT POPULATION PLUS ARMED FORCES OVERSEAS File name File description E8081PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1980, to January 1, 1981 (4 reference dates, 408 records, 90,577 bytes) E8182PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1981, to January 1, 1982 (4 reference dates, 408 records, 90,577 bytes) E8283PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1982, to January 1, 1983 (4 reference dates, 408 records, 90,577 bytes) E8384PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1983, to January 1, 1984 (4 reference dates, 408 records, 90,577 bytes) E8485PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1984, to January 1, 1985 (4 reference dates, 408 records, 90,577 bytes) E8586PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1985, to January 1, 1986 (4 reference dates, 408 records, 90,577 bytes) E8687PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1986, to January 1, 1987 (4 reference dates, 408 records, 90,577 bytes) E8788PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1987, to January 1, 1988 (4 reference dates, 408 records, 90,577 bytes) E8889PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1988, to January 1, 1989 (4 reference dates, 408 records, 90,577 bytes) E8990PQI.TXT Quarterly intercensal estimates of resident population plus Armed Forces overseas, April 1, 1989, to April 1, 1990 (5 reference dates, 510 records, 113,221 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1980 TO APRIL 1, 1990 CIVILIAN POPULATION File name File description E8081CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1980, to January 1, 1981 (4 reference dates, 408 records, 90,577 bytes) E8182CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1981, to January 1, 1982 (4 reference dates, 408 records, 90,577 bytes) E8283CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1982, to January 1, 1983 (4 reference dates, 408 records, 90,577 bytes) E8384CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1983, to January 1, 1984 (4 reference dates, 408 records, 90,577 bytes) E8485CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1984, to January 1, 1985 (4 reference dates, 408 records, 90,577 bytes) E8586CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1985, to January 1, 1986 (4 reference dates, 408 records, 90,577 bytes) E8687CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1986, to January 1, 1987 (4 reference dates, 408 records, 90,577 bytes) E8788CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1987, to January 1, 1988 (4 reference dates, 408 records, 90,577 bytes) E8889CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1988, to January 1, 1989 (4 reference dates, 408 records, 90,577 bytes) E8990CQI.TXT Quarterly intercensal civilian population estimates, April 1, 1989, to April 1, 1990 (5 reference dates, 510 records, 113,221 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1990 FORWARD RESIDENT POPULATION File Name File description E9090RMP.TXT Monthly postcensal resident population estimates, April 1, 1990 to September 1, 1990 (6 reference dates, 612 records, 135,864 bytes) E9091RMP.TXT Monthly postcensal resident population estimates, October 1, 1990 to March 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9191RMP.TXT Monthly postcensal resident population estimates, April 1, 1991 to September 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9192RMP.TXT Monthly postcensal resident population estimates, October 1, 1991 to March 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9292RMP.TXT Monthly postcensal resident population estimates, April 1, 1992 to September 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9293RMP.TXT Monthly postcensal resident population estimates, October 1, 1992 to March 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9393RMP.TXT Monthly postcensal resident population estimates, April 1, 1993 to September 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9394RMP.TXT Monthly postcensal resident population estimates, October 1, 1993 to March 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9494RMP.TXT Monthly postcensal resident population estimates, April 1, 1994 to September 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9495RMP.TXT Monthly postcensal resident population estimates, October 1, 1994 to March 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9595RMP.TXT Monthly postcensal resident population estimates, April 1, 1995 to September 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9596RMP.TXT Monthly postcensal resident population estimates, October 1, 1995 to March 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9696RMP.TXT Monthly postcensal resident population estimates, April 1, 1996 to September 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9697RMP.TXT Monthly postcensal resident population estimates, October 1, 1996 to March 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9797RMP.TXT Monthly postcensal resident population estimates, April 1, 1997 to September 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9798RMP.TXT Monthly postcensal resident population estimates, October 1, 1997 to March 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9898RMP.TXT Monthly postcensal resident population estimates, April 1, 1998 to September 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9899RMP.TXT Monthly postcensal resident population estimates, October 1, 1998 to March 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9999RMP.TXT Monthly postcensal resident population estimates, April 1, 1999 to September 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9900RMP.TXT Monthly postcensal resident population estimates, October 1, 1999 to March 1, 2000 (6 reference date, 204 records, 45,288 bytes) E0000RMP.TXT Monthly postcensal resident population estimates, April 1, 2000 to September 1, 2000, AS RELEASED (Up to 6 reference date, 204 records, 45,288 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1990 FORWARD RESIDENT POPULATION PLUS ARMED FORCES OVERSEAS File name File description E9090PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1990 to September 1, 1990 (6 reference dates, 612 records, 135,864 bytes) E9091PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1990 to March 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9191PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1991 to September 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9192PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1991 to March 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9292PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1992 to September 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9293PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1992 to March 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9393PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1993 to September 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9394PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1993 to March 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9494PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1994 to September 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9495PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1994 to March 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9595PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1995 to September 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9596PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1995 to March 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9696PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1996 to September 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9697PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1996 to March 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9797PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1997 to September 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9798PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1997 to March 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9898PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1998 to September 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9899PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1998 to March 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9999PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 1999 to September 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9900PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, October 1, 1999 to March 1, 2000 (6 reference date, 204 records, 45,288 bytes) E0000PMP.TXT Monthly postcensal estimates of resident population plus Armed Forces overseas, April 1, 2000 to September 1, 2000, AS RELEASED (up to reference dates, 612 records, 135,864 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1990 FORWARD CIVILIAN POPULATION File Name File description E9090CMP.TXT Monthly postcensal civilian population estimates, April 1, 1990 to September 1, 1990 (6 reference dates, 612 records, 135,864 bytes) E9091CMP.TXT Monthly postcensal civilian population estimates, October 1, 1990 to March 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9191CMP.TXT Monthly postcensal civilian population estimates, April 1, 1991 to September 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9192CMP.TXT Monthly postcensal civilian population estimates, October 1, 1991 to March 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9292CMP.TXT Monthly postcensal civilian population estimates, April 1, 1992 to September 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9293CMP.TXT Monthly postcensal civilian population estimates, October 1, 1992 to March 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9393CMP.TXT Monthly postcensal civilian population estimates, April 1, 1993 to September 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9394CMP.TXT Monthly postcensal civilian population estimates, October 1, 1993 to March 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9494CMP.TXT Monthly postcensal civilian population estimates, April 1, 1994 to September 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9495CMP.TXT Monthly postcensal civilian population estimates, October 1, 1994 to March 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9595CMP.TXT Monthly postcensal civilian population estimates, April 1, 1995 to September 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9596CMP.TXT Monthly postcensal civilian population estimates, October 1, 1995 to March 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9696CMP.TXT Monthly postcensal civilian population estimates, April 1, 1996 to September 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9697CMP.TXT Monthly postcensal civilian population estimates, October 1, 1996 to March 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9797CMP.TXT Monthly postcensal civilian population estimates, April 1, 1997 to September 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9798CMP.TXT Monthly postcensal civilian population estimates, October 1, 1997 to March 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9898CMP.TXT Monthly postcensal civilian population estimates, April 1, 1998 to September 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9899CMP.TXT Monthly postcensal civilian population estimates, October 1, 1998 to March 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9999CMP.TXT Monthly postcensal civilian population estimates, April 1, 1999 to September 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9900CMP.TXT Monthly postcensal civilian population estimates, October 1, 1999 to March 1, 2000 (6 reference date, 204 records, 45,288 bytes) E0000CMP.TXT Monthly postcensal civilian population estimates, April 1, 2000 to September 1, 2000, AS RELEASED (up to reference dates, 612 records, 135,864 bytes) NATIONAL POPULATION ESTIMATE DATA APRIL 1, 1990 FORWARD CIVILIAN NONINSTITUTIONAL POPULATION File Name File description E9090SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1990 to September 1, 1990 (6 reference dates, 612 records, 135,864 bytes) E9091SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1990 to March 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9191SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1991 to September 1, 1991 (6 reference dates, 612 records, 135,864 bytes) E9192SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1991 to March 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9292SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1992 to September 1, 1992 (6 reference dates, 612 records, 135,864 bytes) E9293SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1992 to March 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9393SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1993 to September 1, 1993 (6 reference dates, 612 records, 135,864 bytes) E9394SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1993 to March 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9494SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1994 to September 1, 1994 (6 reference dates, 612 records, 135,864 bytes) E9495SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1994 to March 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9595SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1995 to September 1, 1995 (6 reference dates, 612 records, 135,864 bytes) E9596SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1995 to March 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9696SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1996 to September 1, 1996 (6 reference dates, 612 records, 135,864 bytes) E9697SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1996 to March 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9797SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1997 to September 1, 1997 (6 reference dates, 612 records, 135,864 bytes) E9798SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1997 to March 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9898SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1998 to September 1, 1998 (6 reference dates, 612 records, 135,864 bytes) E9899SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1998 to March 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9999SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1999 to September 1, 1999 (6 reference dates, 612 records, 135,864 bytes) E9900SMP.TXT Monthly postcensal civilian noninstitutional population estimates, October 1, 1999 to March 1, 2000 (6 reference date, 204 records, 45,288 bytes) E0000SMP.TXT Monthly postcensal civilian noninstitutional population estimates, April 1, 1999 to September 1, 1999 (up to 6 reference dates, 612 records, 135,864 bytes) II. DATA FILE RECORDS A. Record Layout The 1980s quarterly intercensal and 1990s monthly postcensal national population estimate data files DO NOT have an identical layout, because the 1990s files include a four-character field for year, while the 1980s files use the two final characters, as was common practice prior to 2000. For the 1980s, all records contain 220 characters. All data fields are right-justified. The record layout is as follows. Location Type Data 1-2 Character Series 3-4 Numeric Month 5-6 Numeric Year (last 2 digits) 7-9 Numeric Age (years) 10 (blank) (blank) 11-20 Numeric Total population 21-30 Numeric Total male population 31-40 Numeric Total female population 41-50 Numeric White male population 51-60 Numeric White female population 61-70 Numeric Black male population 71-80 Numeric Black female population 81-90 Numeric American Indian, Eskimo, and Aleut male population 91-100 Numeric American Indian, Eskimo, and Aleut female population 101-110 Numeric Asian and Pacific Islander male population 111-120 Numeric Asian and Pacific Islander female population 121-130 Numeric Hispanic male population 131-140 Numeric Hispanic female population 141-150 Numeric White, non-Hispanic male population 151-160 Numeric White, non-Hispanic female population 161-170 Numeric Black, non-Hispanic male population 171-180 Numeric Black, non-Hispanic female population 181-190 Numeric American Indian, Eskimo, and Aleut, non-Hispanic male population 191-200 Numeric American Indian, Eskimo, and Aleut, non-Hispanic female population 201-210 Numeric Asian and Pacific Islander, non- Hispanic male population 211-220 Numeric Asian and Pacific Islander, non- Hispanic female population For the 1990s, all records contain 222 characters. All data fields are right-justified. The record layout is as follows. Location Type Data 1-2 Character Series 3-4 Numeric Month 5-8 Numeric Year (last 2 digits) 9-11 Numeric Age (years) 12 (blank) (blank) 13-22 Numeric Total population 23-32 Numeric Total male population 33-42 Numeric Total female population 43-52 Numeric White male population 53-62 Numeric White female population 63-72 Numeric Black male population 73-82 Numeric Black female population 83-92 Numeric American Indian, Eskimo, and Aleut male population 93-102 Numeric American Indian, Eskimo, and Aleut female population 103-112 Numeric Asian and Pacific Islander male population 113-122 Numeric Asian and Pacific Islander female population 123-132 Numeric Hispanic male population 133-142 Numeric Hispanic female population 143-152 Numeric White, non-Hispanic male population 153-162 Numeric White, non-Hispanic female population 163-172 Numeric Black, non-Hispanic male population 173-182 Numeric Black, non-Hispanic female population 183-192 Numeric American Indian, Eskimo, and Aleut, non-Hispanic male population 193-202 Numeric American Indian, Eskimo, and Aleut, non-Hispanic female population 203-212 Numeric Asian and Pacific Islander, non- Hispanic male population 213-222 Numeric Asian and Pacific Islander, non- Hispanic female population Within each file, the records are first sorted by the reference date (Month-Year) in chronological order. For each reference date, the first record lists the population counts for all ages combined. The remaining records list the population counts by single year of age in ascending order. B. Explanation of Data Fields (ASCII Files) Series: Quarterly estimates for April 1, 1980, to April 1, 1990 have a series designation of "2I", representing the year of production (1992) and the fact that they are intercensal estimates. Monthly estimates for April 1, 1990 and onward have a series designation "8P", representing the year of production (1998) and the fact that they are postcensal estimates. Month: Monthly estimates for April 1, 1990 and onward designate the months numerically. A "1" indicates population data for January 1; a "2" indicates population data for February 1; and so on. Quarterly estimates for April 1, 1980, to April 1, 1990 designate the first month of each quarter numerically. The monthly reference dates are "1", "4", "7", and "10", for the first day of January, April, July, and October, respectively. Year: Year is identified by the last two digits for the 1980s files, by four digits for the 1990s files. For example, a code of "89" in the 1980s files indicates the year 1989. In the 1990s files the code for 1999 is "1999". Age group: The total population code is 999, which is the first record for each year. This is followed by 0 to 99, which are individual ages, and 100, which is the population 100 years of age and over (centenarians). Sex, race and Hispanic origin: Population data are shown for a total of 21 categories. The first category shows the total population of the age group. The remaining 20 categories list the male and female populations, respectively, for the following racial and/or Hispanic origin categories: Total (All races) White Black American Indian, Eskimo, and Aleut Asian and Pacific Islander Hispanic origin (of any race) Non-Hispanic White Non-Hispanic Black Non-Hispanic American Indian, Eskimo, and Aleut Non-Hispanic Asian and Pacific Islander. III. POPULATION UNIVERSE AND TIME SERIES Estimates for the period from April 1, 1980 through April 1, 1990 are provided in a quarterly time series. These estimates are intercensal, meaning that they are consistent with both the 1980 and 1990 decennial enumerations, but reflect an error of closure in the estimation of population change in the series. For an explanation of the difference between intercensal and postcensal estimates, and other information regarding the methodological basis for these estimates, see Current Population Reports, Series P-25, Number 1095, "U.S. Population Estimates By Age, Sex, Race, and Hispanic Origin: 1980 to 1991." Monthly estimates for the period April 1, 1990 and forward are postcensal estimates, based primarily on the 1990 Decennial Census enumeration and estimates of the population change from the census date to the reference dates of the estimates. Because the 1990 Decennial Census is the only comprehensive enumeration of the United States population in the series, there is no error of closure. Estimates of the United States resident population include people who reside in the 50 States and the District of Columbia. They exclude residents of the Commonwealth of Puerto Rico, and residents of the outlying areas under United States sovereignty or jurisdiction (principally American Samoa, Guam, Virgin Islands of the United States, and the Commonwealth of the Northern Mariana Islands). The definition of residence conforms to the criterion used in the 1990 census, which defines a resident of a specified area as a person "usually resident" in that area. Estimates of resident population exclude the United States Armed Forces overseas, as well as civilian United States citizens whose usual place of residence is outside the United States. Estimates of the resident population plus Armed Forces overseas include United States residents and members of the Armed Forces on active duty stationed outside the United States, but exclude military dependents and other United States citizens living abroad. Civilian population estimates include United States residents not in the active duty Armed Forces. The difference between resident population plus Armed Forces overseas and civilian population is the worldwide Armed Forces population. This population includes the following groups: regular active duty military personnel as reported in military strength statistics of the five Armed Forces branches in the Departments of Defense and Transportation, reserve forces on three and six months active duty for training, National Guard reserve forces on active duty for four months or more, and students at the military academies. Estimates of the Armed Forces overseas generally include personnel reported by their respective branch of the Armed Forces as stationed outside the United States. The Navy overseas estimates include personnel ashore at overseas locations, personnel located on Naval vessels whose home-ports are outside the United States, and personnel located on Naval vessels deployed to the overseas fleets. Estimates of the civilian noninstitutional population, available for dates after April 1, 1990, differ from the civilian population estimates in that they exclude people residing in institutions. Such institutions consist primarily of nursing homes, prisons, jails, mental hospitals, and juvenile correctional facilities. While the civilian noninstitutional population has been adopted as the universe for many sample surveys, the current release is not consistent with results of current surveys conducted by the Census Bureau. One such survey is the Current Population Survey, which calibrated its results to 1980-census-based projections through 1993. From 1994 onward, the survey calibrated its results to 1990-census-based projections that have been adjusted for net underenumeration based on the 1990 Post Enumeration Survey. IV. THE ESTIMATES BASE POPULATION While the 1990 Decennial Census defines most of the base population for these estimates, the total resident population for April 1, 1990 (248,790,925) does not agree precisely with the 1990 census figure as originally published (248,709,873). The difference, as reflected throughout the entire postcensal estimates series, arises from the sources described below: (1) The estimates include census count question resolution corrections determined through the Census Quality Review process. These corrections of census tabulations, which are not related to underenumeration, came after the publishing of the initial 1990 census results. (2) The estimates include population adjustments associated with the underenumeration that resulted in the eight test sites from the 1995 Census Test. These test sites include Oakland, California; Paterson, New Jersey; and six Louisiana parishes (Bienville, De Soto, Jackson, Natchitoches, Red River, and Winn). In addition, the estimates include adjustments associated with underenumeration in the 1998 census dress rehearsals in Sacramento, California, and Menominee County, Wisconsin. An administrative requirement for local estimates to conform to these adjusted counts necessitated a revision of the national population definition to include the adjustments. With the exception of the 1995 test census sites, the population does not include adjustments for underenumeration. In particular, the sample-based "dual system" estimates of underenumeration derived from the 1990 Decennial Census Post Enumeration Survey, included in the results of many federal surveys, are not included in these estimates. Aside from the changes affecting total population, modifications were made in the distribution of the population by age and race. These modifications brought the definition of age and race into conformity with definitions used for data from other sources, such as vital statistics. The age distribution of the estimates base population, while census-based, differs with the distribution shown in the 1990 census publications. Such modifications brought the definition of age into conformity with definitions used for data from other sources, such as vital statistics. The aim was to correct biases in census age tabulations that resulted from displacement of age reporting from the reference date of the census. In 1990 census publications, age is based on respondents' direct reports of age at last birthday, with some editing for age misstatement. This definition proved inadequate for postcensal estimates, as it was apparent that many respondents reported their age (even if reported correctly) at the time of completion of the census form or interview by an enumerator. These reported ages usually occurred up to several months after the April 1 reference date, resulting in an upward biased age. Modification was based on a re-specification of age, for most individual respondents, according to their year of birth. Age was derived from year of birth by allocating date of birth to the first quarter and last three quarters of each year, subtracting year of birth from 1990 for those born before April 1, and from 1989 for those born after April 1. The allocation was based on a historical series of registered births by month. As with age, the census-based race distribution of the estimates base population differs with the distribution shown in the 1990 census publications. Such modifications brought the definition of race into theoretical conformity with other sources, such as vital statistics. The modification conformed to the definition of race specified in Office of Management and Budget Directive 15. In the 1990 census, a substantial number of people (roughly 9.8 million) did not specify a racial group that could be classified as any of the White, Black, American Indian, Eskimo, Aleut, Asian, or Pacific Islander categories on the census form. A large majority of these respondents were of Hispanic origin, based on their response to a separate Hispanic origin question on the form. Most wrote in "Hispanic" or their Hispanic origin type (such as "Mexican" or "Puerto Rican") as their race. People of unspecified race were allocated to one of the four tabulated racial groups (White; Black; American Indian, Eskimo, and Aleut; Asian and Pacific Islander) based on their response to the Hispanic origin question. While this modification does not ensure that race reporting will be consistent among data sources, it enables the use of varying sources of data in the estimation process, with appropriate adjustment of categories. V. POSTCENSAL ESTIMATION OF RESIDENT POPULATION A. Estimation of Population By Sex, Race, and Hispanic Origin Estimates of the United States population by 16 combinations of sex (male, female), race (White; Black; American Indian, Eskimo, and Aleut; Asian and Pacific Islander), and Hispanic origin (Hispanic, Non-Hispanic) were derived quarterly by updating the resident population enumerated in the 1990 census through the components of population change. The following formula was applied to update each group: (1) 1990 enumeration of resident population, (2) + births to U.S. resident women, (3) - deaths to U.S. residents, (4) + net international migration, (5) + net movement of U.S. Armed Forces and civilian citizens to the United States. B. Estimation of Components of Population Change While the estimates base population was described in the previous section as being primarily a consequence of the 1990 Decennial Census, the components of change - births, deaths, and both major classes of net migration - are estimated from administrative sources. (1) Registered births to United States resident women are estimated from tabulations of data on birth certificates, as supplied by the National Center for Health Statistics. The primary source for these birth data can be found in the National Center for Health Statistics Monthly Vital Statistics Report, Volume 47, Number 18, "Births: Final Data for 1997," and similar reports for other years. Generally, it is assumed that the coding of race and Hispanic origin of mother on birth certificates is consistent with the reporting of race and Hispanic origin of children in the census. Because of apparent serious discrepancies in the reporting of race for the Hispanic origin population between the census and birth certificates, however, cross-categories of race and Hispanic origin are built on the assumption that rates of childbearing among Hispanic women do not vary by race. (2) Registered deaths to United States residents by sex and race are estimated from tabulations of data on death certificates, as supplied by the National Center for Health Statistics. The primary source for this death data can be found in the National Center for Health Statistics National Vital Statistics Report, Volume 47, Number 19, "Deaths: Final Data for 1997," and similar reports for other years. It is assumed that reporting of race on death certificates is consistent with reporting of race in the census. Because of the number of decedents of unknown Hispanic origin is large, age-specific Hispanic death rates are calculated for a large proportion of the states where reporting of Hispanic origin is complete. These rates are then used to estimate Hispanic deaths for the entire U.S. population. (3) The international net migration components are based on a variety of administrative sources and analytic estimates. The Immigration and Naturalization Service supplies data on legal immigrants. The Office of Refugee Resettlement supplies data on people admitted to the United States as refugees. Net migration from Puerto Rico to the United States is projected at a constant level, based on an estimate of annual net migration out of the Commonwealth during the 1980s, as developed by the Census Bureau's International Programs Center. Subtracting legal immigrants to the island during the 1980s, and assuming that undocumented migration and the emigration of legal residents from the island net to zero, yields an estimate of net migration from Puerto Rico to the United States. The (presumably small) balance of migration between the United States and other outlying areas under United States jurisdiction is assumed to be zero. Because international migration data sources generally code country of birth or citizenship rather than race and Hispanic origin, tabulations of country of birth by race by Hispanic origin from the 1990 census are used to impute race and Hispanic origin of migrants. Two numerically substantial types of international migration for which reliably accurate and current data are unavailable are undocumented immigration (both in and out of the United States) and the permanent emigration of legal residents. Undocumented immigration refers to the net increase of the undocumented population due to change in residence across the national border by aliens, either by unauthorized entry or by overstaying a temporary (non-immigrant) visa, discounting those that subsequently immigrate legally. For undocumented immigration, we make an allowance of 225,000 net migration per year, which is constant throughout the postcensal estimating period. The race and Hispanic origin of this flow is based on distributions by country of birth estimated by the Immigration and Naturalization Service, and imputed by tabulations of race by Hispanic origin by country of birth from the 1990 census. Calculating the emigration of legal residents requires calculating native and foreign-born emigration separately. Foreign-born emigration counts incorporated results of research carried out at the Census Bureau and published as Population Division Technical Working Paper #9, "Estimates of the Emigration of the Foreign-Born Population: 1980 to 1990," authored by Bashir Ahmed and J. Gregory Robinson. These estimates for the 1980s were used to calculate rates of emigration for the foreign-born population, which were projected through the 1990s. Legal native resident emigration counts relied on an allowance of 48,000 per year, based on Population Division Technical Working Paper #10, "Estimation of the Annual Emigration of U.S. Born Persons by Using Foreign Censuses and Selected Administrative Data: Circa 1980," authored by Edward Fernandez. Also included was an allowance for the net migration of non-refugee temporary residents (most of which are foreign students and scholars) who would be enumerated in the decennial census as residents of the United States. This allowance is intended to preserve the age, sex, race, and Hispanic origin distribution of the population as estimated for the 1990 census date. (4) The temporary movement of federally affiliated United States citizens consists mostly of movement of the active duty Armed Forces and Armed Forces dependents between the United States and overseas. Also included is the movement of civilian federal employees and their dependents. We estimate the migration of federally affiliated citizens by observing trends in the number of personnel abroad, from three sources: a) Armed Forces overseas strength statistics are supplied by the five branches of the Armed Forces in the Departments of Defense (Army, Navy, Marines, and Air Force) and Transportation (Coast Guard). b) The number of military dependents residing overseas is published by the Department of Defense, for four branches of the Armed Forces (excluding Coast Guard). These data come from the Department of Defense, Directorate for Information, Operations, and Reports, "Worldwide Manpower Distribution by Geographic Area." c) The number of civilian Federal employees overseas is supplied by the Office of Personnel Management. This number is inflated to include dependents. These data come from the United States Office of Personnel Management, Federal Civilian Workforce Statistics, "Employment and Trends" series. The inference of net migration from this population to the United States follows a reverse component-of-change logic applied to the federally affiliated overseas population. The net increase in the overseas Federal population, minus net recruits to this population from abroad (for example, residents of outlying areas joining the Armed Forces), minus births, plus deaths, provides an estimate of the net migration to the overseas Federal population from the United States. The negative of this estimate is the estimated migration of federally affiliated citizens to the United States from overseas. Distributions of the Armed Forces overseas by race, Hispanic origin, and nativity are supplied by the Department of Defense, Defense Manpower Data Center. These distributions are imputed to the balance of the overseas federally affiliated population, most of which are Armed Forces dependents. The reverse component-of-change logic is applied to each race-origin cross-category. The net migration of United States citizens not affiliated with the Federal government, as well as the temporary movement of students, scholars, and embassy personnel, are tacitly assumed to be zero, although these movements do, in fact, represent a change of residence in and out of the United States according to the residence definition used in the estimates. C. Estimation of Population By Age (1) The inflation-deflation method. Once the postcensal population estimates by sex, race, and Hispanic origin are computed, the age distribution of each sex-race-Hispanic category is estimated by the inflation-deflation method. This method seeks to allow each age group in the census base population to advance one year of age for each year after the census, reflecting the effects of births, deaths and migration, while preserving - without aging - the age pattern of census undercoverage and age misreporting estimated for the base population. The method is described in detail in Current Population Reports, Series P25, Number 1095, "U.S. Population Estimates, by Age, Sex, Race, and Hispanic Origin: 1980 to 1991," pp. xvii-xviii. (2) Components of change by age. Deaths to United States residents by age (single years through age 69, and the total of ages 70 and over), sex, and race are based on official tabulations of deaths by single year of age from the National Center for Health Statistics. The age distribution of deaths to residents 70 years of age and over are based on rates computed from life tables, and proportionally adjusted to be consistent with the National Center of Health Statistics' total deaths to people 70 and over. For the Hispanic population by sex and race, the 1990, 1992, and 1994 Hispanic life tables are applied to produce Hispanic deaths by age, sex, and race. Non-Hispanic deaths are then derived as total minus Hispanic, within categories of age, sex, and race. For legal alien immigrants admitted by the Immigration and Naturalization Service, age and sex is available on the individual immigrant records. For refugee categories, the age distribution is based on distributions of refugees of the same country of birth adjusting to permanent immigrant status through the Immigration and Naturalization Service, also from the individual immigrant records. We estimated the age distribution of federally affiliated United States citizens by the method of cohort survival, using age distributions of Armed Forces overseas supplied by the Department of Defense's Defense Manpower Data Center, as well as distributions of overseas Armed Forces dependents from the 1970 census, and overseas civilian federal employees from the Office of Personnel Management. D. Estimation of Population By Quarter and Month All of the postcensal population detail shown in these files was produced for monthly reference dates, although the calendar quarter was the basic time interval for estimating distributions of components of change by age, sex, race, and Hispanic origin. For the most part, the data sources for components of change provide monthly data, to the extent that the data are final. For some preliminary data, the monthly series incorporated projections of seasonal distributions from final data for earlier years. Data from the Immigration and Naturalization Service and Office of Refugee Resettlement on legal alien immigration and refugees, respectively, were available by month. Most Armed Forces strength data by branch of service, used to infer movement of Armed Forces from overseas, were available by month, whereas data on Armed Forces dependents, and all Armed Forces demographic detail before 1993, were available by quarter. No seasonal information was available for undocumented immigration, emigration of legal residents, net migration from Puerto Rico to the United States, and net migration of non-refugee temporary residents, so no seasonality was assumed. For births, deaths, and legal alien immigrants, quarterly distributions by age, sex, race, and Hispanic origin were independently derived. For other components, sex, race, and Hispanic origin distributions were imputed to quarterly data; either from the current calendar year or fiscal year, or on the basis of a projection from a past year. The procedure for estimating the population by quarter, once the quarterly components of change were estimated, followed the procedure described above. The single-year age distribution of the base population was further distributed to quarter-year of age in proportion to registered births in the birth year of each cohort. The inflation-deflation method was employed to the quarter-year of age population, as updated through components of change by age, sex, race, and Hispanic origin. To complete the population detail for the remaining months that do not begin a calendar quarter, we estimated monthly series of births, deaths, and all of the components of immigration, by sex, race, and Hispanic origin. Aggregate monthly components - births, deaths, international migration, and federal United States citizen migration - were expanded to month-of-birth cohort, by imputation from quarterly data. The resulting monthly series of month-of-birth cohort components were applied to population estimates for quarterly dates to produce the monthly population detail.