Documentation is extracted from PPL-57 Source: U.S. Bureau of the Census Release date: March 24, 1997 U.S. Population Estimates by Age, Sex, Race, and Hispanic Origin: 1990 to 1996 March, 1997 The attached tables present annual estimates of the resident population of the United States, with components of change. Table 1 is devoted to demographic detail, showing annual July 1 estimates of resident population by single year of age, sex, race, and Hispanic origin, for 1990 to 1996, with comparable data for the census date of April 1, 1990. Tables 2 and 3 are devoted to the accounting of population change, showing births, deaths, and migration across the U.S. borders, from the census date of April 1, 1990, until January 1, 1997. Table 2 provides components of change for the total resident population by month; table 3 provides components of change by calendar year, and by race and Hispanic origin. The population estimates are not adjusted for net underenumeration in the 1990 census. However, they incorporate a small increase (8,418 persons) in the April 1, 1990 census population from count resolution corrections processed through March, 1994. The series is consistent with currently published annual estimates of the population prior to 1990 by age, sex, and race, as they appear in Current Population Reports, series P25, numbers 311, 519, 917, and 1095, except that estimates for the 1980's in P25-1095 do not reflect count resolution corrections to the 1990 census. The current series supersedes 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 still preliminary and subject to future revision. Population Universe Estimates of the U.S. resident population in this report include persons resident 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 U.S. 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 U.S. Armed Forces overseas, as well as civilian U.S. citizens whose usual place of residence is outside the United States. Estimates of the resident population plus Armed Forces overseas (available on request) include U.S. residents and members of the Armed Forces on active duty stationed outside the United States, but do not include military dependents and other U.S. citizens living abroad. Civilian population estimates (also available on request) include U.S. 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 includes regular active duty military personnel as reported in military strength statistics of the five branches of the Armed Forces in the Departments of Defense and Transportation, reserve forces on 3- and 6-months active duty for training, National Guard reserve forces on active duty for 4 months or more, and students at the military academies. Estimates of the Armed Forces overseas generally include persons reported by their respective branch of the Armed Forces as stationed outside the United States; for the Navy, they include persons ashore at overseas locations or located on Naval vessels either homeported outside the United States, or deployed to the overseas fleets. Estimates of the civilian noninstitutional population, also available on request, differ from the civilian population in that they exclude persons residing in institutions, primarily nursing homes, prisons and 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 through the end of 1993, including the Current Population Survey (CPS), which were calibrated to 1980-census-based projections. Current estimates for dates from January 1, 1994, onward, are not consistent with the results of those surveys, including the CPS, which are calibrated to projections that have been adjusted for net underenumeration based on the 1990 Post Enumeration Survey. The 1990 Census Base Population Although the enumeration of resident population in the 1990 census, without adjustment for net undercoverage, was adopted as a standard for the estimates, changes were made in the distribution of the population by age and race. These modifications were made in order to bring the definition of age and race into conformity with definitions used for data from other sources,such as vital statistics. For age, 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 correctly) at the time of completion of the census form or interview by an enumerator, either of which could have occurred several months after the April 1 reference date. As a result, age was biased upward. Modification was based on a respecification 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. For race, the objective of the modification was to conform to the definition of race specified in Office of Management and Budget (OMB) Directive 15. In the 1990 census, a substantial number of persons (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 persons were of Hispanic origin (based on their response to a separate, Hispanic origin question on the form), and many wrote in their Hispanic origin, or Hispanic origin type (for example, Mexican or Puerto Rican) as their race. Persons of unspecified race were allocated to one of the four tabulated racial groups (White, Black, American Indian, Asian and Pacific Islander) based on their response to the Hispanic origin question. These four race categories conform with OMB Directive 15, and are more consistent with the race categories in other administrative sources (such as vital statistics) than are the original census tabulations. As was the case with age modification, the procedure was carried out through assignment of modified race on individual census records. Postcensal Estimation of Resident Population by Sex, Race, and Hispanic Origin Estimates of the U.S. population by 16 categories of sex, race, and Hispanic origin, 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. Estimation of the components of population change. A detailed description of the sources of data for the components of change, and their method of estimation, is available in United States Population Estimates, by Age, Sex, Race, and Hispanic Origin: 1980 to 1988, Current Population Reports, series P-25, number 1045, pages 34 to 39. The following is a summary update of these data sources and procedures. (1) Registered births to U.S. resident women are estimated from data supplied by the National Center for Health Statistics (NCHS). Distributions of births by sex, by race of mother, and by Hispanic origin of mother, were based on microdata files supplied through calendar year 1994 by NCHS from their registration system. To estimate the distribution of births by race and Hispanic origin of mother, for 1995 and the first half of 1996, we applied projected age-specific birth rates, for women in each racial group and for women of Hispanic origin, to preliminary estimates of the number of resident women. In the case of 1995, we adjusted the resulting births proportionately to sum to the preliminary annual estimates of total births and births by selected age groups, sex, and four races, supplied by NCHS from their 90 percent sample of final 1995 births. To obtain cross-categories of race with Hispanic origin for all years, we distributed Hispanic origin births according to the distribution of Hispanic women 15 to 44 years of age by race in the 1990 census. Non-Hispanic births by race group were obtained by subtracting Hispanic births from all births. (2) Registered deaths to U.S. residents by sex and race are also supplied by NCHS. Final data were available through 1994. To estimate the distribution of deaths by race and Hispanic origin, for 1995 and the first half of 1996, we applied projected age-specific mortality rates to preliminary estimates of the population by single year of age, sex, race, and Hispanic origin. In the case of 1995, we adjusted the resulting deaths proportionately to sum to the preliminary annual estimates for total deaths and deaths for selected age groups, sex, and four races, supplied by NCHS from their 90 percent sample of final 1995 deaths. For purposes of seasonality, preliminary estimates of deaths, with distribution by sex and 3 race categories (White, Black, and all other) based on the 10 percent Current Mortality Sample, were available through 1995, and the first four months of 1996. Preliminary deaths to the American Indian, and Asian and Pacific Islander populations by sex were projected using life tables, with proportional adjustment to sum to the other-races total. Hispanic origin deaths, for all years, by sex and race were also estimated using life tables, applied to a distribution of the Hispanic population by age, sex, and race. (3) The international net migration components are based on a variety of administrative sources and analytic estimates. The Immigration and Naturalization Service (INS) supplies data on legal immigrants. The Office of Refugee Resettlement (ORR) supplies data on persons admitted to the United States as refugees. Both of these sources supply data on country of birth. We estimate the distribution by race and Hispanic origin from the country-of-birth tallies, along with the racial and origin distribution of foreign-born migrants to the United States, from the census 20 percent sample. Data from the 1990 census on foreign-born migration from 1985 to 1990 were used for this purpose. The International Programs Center of the U.S. Bureau of the Census supplies data on net migration between the United States and Puerto Rico, by age and sex. The distribution of Puerto Rican migration by age, sex, race, and Hispanic origin, is assumed constant, and is based on the distribution of migrants from Puerto Rico to the United States, 1985 to 1990, from the 1990 census 20 percent sample, and the distribution of migrants from the United States to Puerto Rico, 1985 to 1990, from the 1990 census of Puerto Rico. The (presumably small) balance of migration between the U.S. and other outlying areas under U.S. jurisdiction is assumed to be zero. We include 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. The dynamic underlying this assumption is that of a constant population which exactly offsets the effects of its mortality and its aging through net migration from abroad. While the total net migration for a given year will be equal to a life-table based estimate of the number of deaths to the population stock, the age distribution will show positive and negative migration at different ages of larger absolute magnitude. 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 U.S.) 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. For emigration of legal residents, we assume 222,000 a year, based on annual allowances of 195,000 foreign-born and 27,000 native born emigrants. (4) The temporary movement of Federally affiliated U.S. 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). Distributions by sex, race, and Hispanic origin are derived from separate tabulations provided by the Defense Manpower Data Center (Department of Defense), giving demographic detail by duty location and branch of service. 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). We assume the race distribution to be the same as the race distribution of the Armed Forces overseas. The distribution by sex is based on information on military dependents residing abroad from the 1970 census of the population of U.S. citizens residing overseas. c) The number of civilian Federal employees overseas is supplied by the Office of Personnel Management (OPM), and is inflated to include dependents. 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. The net migration of U.S. 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. Estimation of the Population by Age 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 estimated for the base population. The method is described in detail in U.S. Population Estimates, by Age, Sex, Race, and Hispanic Origin: 1980 to 1991, Current Population Reports, P25-1095, pp. xvii-xviii. Components of change by age. Deaths to U.S. residents by age, sex and race under age 70, and the total for 70 and over, are based on official tabulations of deaths by single-year-of-age from the National Center for Health Statistics (NCHS). 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 NCHS total deaths to persons 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 (INS), age and sex are 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 INS, also from the individual immigrant records. We estimated the age distribution of Federally affiliated U.S. citizens by the method of cohort survival, using age distributions of Armed Forces overseas supplied by the Department of Defense, 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 (OPM). Estimation of the Population by Quarter and Month All of the population detail shown in this report were also 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, monthly series were imputed by projection of seasonal distributions from final data for earlier years. Data from the INS and ORR on legal alien immigration and refugees 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 subcomponents of immigration, by sex, race, and Hispanic origin. Aggregate monthly components--births, deaths, international migration, and Federal U.S. 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. Current and Future Revisions to National Population Estimates Methodology For the first time, we expanded migration accounting to include an allowance for the age distribution of non-refugee temporary residents (mostly foreign students and scholars) who enter and leave the country legally, and are subject to enumeration in a census, but are not permanent immigrants, as defined by INS. While the net gain or loss to the total population from this source is small, the accounting of non-refugee temporary residents should improve estimates of age distribution: because the migration is temporary, migrants do not remain in the population to grow older with passing years, as is assumed for the balance of the population. We have revised our assumption regarding net migration from Puerto Rico to the United States. Due to the unreliability of Puerto Rican passenger traffic data as a proxy for net migration from Puerto Rico to the United States, we decided to discontinue our sole reliance on that data series. Instead, we estimated this net flow of migrants using a projection prepared by the International Programs Center of the U.S. Bureau of the Census. A further technical development that is new with this series of estimates is the inclusion of new data on the characteristics of undocumented residents legalizing their residency status under provisions of the Immigration Reform and Control Act of 1986 (IRCA). While not affecting the total number of undocumented aliens, this change resulted in a substantial increase in the Hispanic origin share of undocumented immigration, and an increase in the population of males ages 16 to 39 at the expense of those under age 16. Finally, a technical development that is new with this series, is the change in methodology for estimating the age distribution of emigrants. While not affecting the total number of emigrants, this change resulted in a noticeable shift in the age structure of both the Asian and Pacific Islander populations and the Hispanic population (of all races). Unpublished Data, Alternative Media, and Related Reports The following additional detailed information is also available for separate purchase, after March 15, 1997. (1) Population detail, as shown in table 1 for the resident population, will be available as a quarterly series for the resident population, resident population plus Armed Forces overseas, and civilian population. These will appear as PPL-57, Appendices A through C. (2) Similar detail was available for the civilian noninstitutional population, for July 1 of 1990, 1991, 1992, 1993, 1994, and 1995, and for the first of each month from January 1, 1996, to January 1, 1997, inclusive. (We include monthly data for 1996, because this universe is often used for controls of surveys, that may occur on dates other than July 1). These data will be identified as PPL-57, Appendix D. (3) Quarterly single-year age detail for the population 65 years of age and older will be available, as PPL-57, Appendix E. These data will match the three population universes in (1) above, as they coincide for ages 65 and over. (4) Births, deaths, and various components of migration, by age, sex, race, Hispanic origin, and calendar quarter, consistent with estimates through January 1, 1997, will also be available as PPL-57, Appendix F. (5) Population detail, as shown in the attached tables for July 1 dates, are also available for monthly dates since April 1, 1990. Generally, monthly estimates are available two to three months after the reference date; the most recent available month that is imminent at the time of this writing is January 1, 1997. It should be noted that estimates for dates in the second half of 1996 and 1997 are very provisional, and are not consistent with official estimates for July 1, 1997, to be released between the end of 1997 and mid-1998. All population data released with this report are available as hard-copy tables. The entire monthly population series through January 1, 1997, will also be placed on personal computer (floppy) diskette, in both ASCII and spreadsheet format. Unpublished data may be obtained by writing to the Statistical Information Staff, Population Division, Bureau of the Census, Washington, D.C., 20233. Requests for products or pricing information may be sent via electronic mail to Internet address POP@CENSUS.GOV; however, products are currently provided only through regular mail, at cost of reproduction.