The U.S. Income Distribution: Trends and Issues. Congressional Research Service, Library of Congress. Sarah A. Donovan, Marc Labonte, Joseph Dalaker. December 8, 2016
Income inequality—that is, the extent to which individuals’ or households’ incomes differ—has increased in the United States since the 1970s. Rising income inequality over this time period is driven largely by relatively rapid income growth at the top of the income distribution. For example, in 1975, the average income of households in the top fifth of income distribution was 10.3 times as large as average household income in the bottom fifth of the distribution; in 2015, average top incomes were 16.3 times as large as those at the bottom.
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