Census Bureau Answer on Question: Are Rich Getting Richer?

Here is what the US Census Bureau had to say back in June, 2000 when most of us were not paying much attention to this issue.

“Historical Census Bureau income statistics can shed some light on this debate. Although the Census Bureau has been measuring income for a half-century, and a large number of factors have been identified as contributing to changes in inequality, the causes are still not entirely understood.

The Current Population Survey (CPS) is a rich source of data on income inequality.  During the past 50 years, the annual demographic supplement to the March CPS has provided researchers with a wealth of data on the income distribution.  Since 1947, the Census Bureau has employed a commonly used measure, the Gini coefficient (also known as the index of income concentration), to measure family income inequality.  With two exceptions, the Gini coefficient decreased between 1947 and 1968.  During this period, the Gini for families indicated a decrease in income inequality of 7.5 (±2.1) percent.    Since 1968, however, this trend has reversed.  Income inequality for families, measured by the Gini coefficient, increased between 1968 and 1998 (see Figure 1). The net effect over the entire 1947-1998 period is an increase in family income inequality.”http://www.census.gov/prod/2000pubs/p60-204.pdf

Household Share of Aggregate Income by Fifths of the Income Distribution   1967 to 1998  as a Percent of Total US Income Per Fifth
Year	Lowest 20%	LowMiddle 20%	Middle 20%	HighMiddle 20%	Highest 20%	Top 5%
1998	3.6	9.0	15.0	23.2	49.2	21.4
1997	3.6	8.9	15.0	23.2	49.4	21.7
1996	3.7	9.0	15.1	23.3	49.0	21.4
1995	3.7	9.1	15.2	23.3	48.7	21.0
1994	3.6	8.9	15.0	23.4	49.1	21.2
1993	3.6	9.0	15.1	23.5	48.9	21.0
1992	3.8	9.4	15.8	24.2	46.9	18.6
1991	3.8	9.6	15.9	24.2	46.5	18.1
1990	3.9	9.6	15.9	24.0	46.6	18.6
1989	3.8	9.5	15.8	24.0	46.8	18.9
1988	3.8	9.6	16.0	24.3	46.3	18.3
1987	3.8	9.6	16.1	24.3	46.2	18.2
1986	3.9	9.7	16.2	24.5	45.7	17.5
1985	4.0	9.7	16.3	24.6	45.3	17.0
1984	4.1	9.9	16.4	24.7	44.9	16.5
1983	4.1	10.0	16.5	24.7	44.7	16.4
1982	4.1	10.1	16.6	24.7	44.5	16.2
1981	4.2	10.2	16.8	25.0	43.8	15.6
1980	4.3	10.3	16.9	24.9	43.7	15.8
1979	4.2	10.3	16.9	24.7	44.0	16.4
1978	4.3	10.3	16.9	24.8	43.7	16.2
1977	4.4	10.3	17.0	24.8	43.6	16.1
1976	4.4	10.4	17.1	24.8	43.3	16.0
1975	4.4	10.5	17.1	24.8	43.2	15.9
1974	4.4	10.6	17.1	24.7	43.1	15.9
1973	4.2	10.5	17.1	24.6	43.6	16.6
1972	4.1	10.5	17.1	24.5	43.9	17.0
1971	4.1	10.6	17.3	24.5	43.5	16.7
1970	4.1	10.8	17.4	24.5	43.3	16.6
1969	4.1	10.9	17.5	24.5	43.0	16.6
1968	4.2	11.1	17.5	24.4	42.8	16.6
1967	4.0	10.8	17.3	24.2	43.8	17.0

When did household income inequality increase?

“Whereas the data on household income inequality between 1967 and 1980 are ambiguous, it is clear that the household income distribution became increasingly unequal beginning in 1981.  Although between 1980 and 1981 the only summary measures to increase significantly were the Atkinson (e = 0.75) and the MLD, these changes signified the beginning of a period marked by rising household income inequality.”  http://www.census.gov/prod/2000pubs/p60-204.pdf

What do these numbers look like now?

Household Share of Aggregate Income by Fifths of the Income Distribution   2009 and 2010 Percent of Total US Income Per Fifth
Year	Lowest 20%	LowMiddle 20%	Middle 20%	HighMiddle 20%	Highest 20%	Top 5%
2010	3.3	8.5	14.6	23.4	50.2	21.3
2009	3.4	8.6	14.6	23.2	50.3	21.7

http://www.census.gov/prod/2011pubs/p60-239.pdf