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Historical Income Tables Footnotes

Footnotes for Historical Income Tables from the Current Population Survey (CPS),
Annual Social and Economic Supplement (ASEC)

Please note that not all footnotes apply to all tables

NA Not available.
B Base less than 75,000.
X Not applicable.
- Zero or rounds to zero.
1/ Before 1983, based on CPI-U-X1
2/ Before 1967, CPI factors are extrapolated.
3/ Before 1967, data are for "Black and other races" combined
4/ People of Hispanic origin may be of any race.
5/ Data based on 1940 census population controls.
6/ Data reflect implementation of expanded income questions to show wage and salary, farm self-employment, nonfarm self-employment, and all other nonearned income separately.
7/ Data reflect implementation of 1950 census population controls.
8/ Data reflect implementation of first hotdeck procedure to impute missing income entries (all income data imputed if any missing). Data also reflect introduction of 1960 census-based sample design.
9/ Data reflect full implementation of 1960 census-based sample design and population controls.
10/ Data reflect implementation of new procedures to impute missing data only.
11/ Questionnaire expanded to ask eight income questions.
12/ Data reflect implementation of a new March CPS processing system.
13/ Data reflect introduction of 1970 census-based sample design and population controls.
14/ Data reflect full implementation of 1970 census-based sample design.
15/ Data reflect implementation of a new March CPS processing system. Questionnaire expanded to ask 11 income questions.
16/ Some of these estimates were derived using Pareto interpolation and may differ from published data which were derived using linear interpolation.
17/ First year medians were derived using both Pareto and linear interpolation. Before this year, all medians were derived using linear interpolation.
18/ Data reflect implementation of 1980 census population controls. Questionnaire expanded to show 27 possible values from 51 possible sources of income.
19/ Data reflect implementation of Hispanic population weighting controls and introduction of 1980 census-based sample design.
20/ Recording of amounts for earnings from longest job were increased to $299,999. Data reflect full implementation of 1980 census-based sample design.
21/ Data reflect implementation of a new March CPS processing system.
22/ Data reflect implementation of 1990 census population controls.
23/ Data collection method changed from paper and pencil to computer-assisted interviewing. In addition, the March 1994 income supplement was revised to allow for the coding of different income amounts on selected questionnaire items. Child support and alimony limits decreased to $49,999. Limits increased in the following categories: earnings to $999,999; social security to $49,999; supplemental security income and public assistance income to $24,999; and veterans' benefits to $99,999.
24/ Data reflect introduction of 1990 census-based sample design.
25/ Data reflect full implementation of the 1990 census-based sample design and metropolitan definitions, 7,000 household sample reduction, and revised race edits.
26/ Starting in 1999, alternative income definition 7 includes federal EIC and EIC for the nine states that use federal eligibility rules to compute the state credit as a percentage of the federal EIC. The nine states are: Iowa, Kansas, Massachusetts, Maryland, New York, Oregon, Rhode Island, Vermont, and Wisconsin.
27/ Starting in 1999, 50th percentile is based on micro-sorted data.
28/ The CPI-U-RS is a price index of inflation that incorporates most of the improvements in methodology made to the current CPI-U since 1978 into a single, uniform series. See Money Income in the United States: 1999 or the appendix of Money Income in the United States: 1998 for more information. Before 1977 the CPI-U-RS is extrapolated.
29/ Implementation of Census 2000 - based population controls.
30/ Implementation of a 28,000 household sample expansion.
31/ Beginning with the 2003 CPS, respondents were allowed to choose one or more races. White alone refers to people who reported White and did not report any other race category. The use of this single-race population does not imply that it is the preferred method of presenting or analyzing data. The Census Bureau uses a variety of approaches. Information on people who reported more than one race, such as White and American Indian and Alaska Native or Asian and Black or African American, is available from Census 2000 through American Factinder. About 2.6 percent of people reported more than one race in Census 2000.
32/ For the year 2001 and earlier, the CPS allowed respondents to report only one race group.
33/ Black alone refers to people who reported Black and did not report any other race category.
34/ Asian alone refers to people who reported Asian and did not report any other race category.
35/ Data have been revised to reflect a correction to the weights in the 2005 ASEC.
36/ Beginning with 2009 income data, the Census Bureau expanded the upper income interval used to calculate medians and Gini indexes to $250,000 or more. Medians falling in the upper open-ended interval are plugged with "$250,000." Before 2009, the upper open-ended interval was $100,000 and a plug of "$100,000" was used.
37/ Implementation of Census 2010-based population controls.
38/ Data are based on the CPS ASEC sample of 68,000 addresses. The 2014 CPS ASEC included redesigned questions for income and health insurance coverage. All of the approximately 98,000 addresses were eligible to receive the redesigned set of health insurance coverage questions. The redesigned income questions were implemented to a subsample of these 98,000 addresses using a probability split panel design. Approximately 68,000 addresses were eligible to receive a set of income questions similar to those used in the 2013 CPS ASEC and the remaining 30,000 addresses were eligible to receive the redesigned income questions. The source of the 2013 data for this table is the portion of the CPS ASEC sample which received the income questions consistent with the 2013 CPS ASEC, approximately 68,000 addresses.


Source: U.S. Census Bureau | Income |  Last Revised: September 16, 2014