In this Pew research study, which examines the changing size, demographic composition and economic fortunes of the American middle class, “middle-income” Americans are defined as adults whose annual household income is two-thirds to double the national median, about $42,000 to $126,000 annually in 2014 dollars for a household of three.3 Under this definition, the middle class made up 50% of the U.S. adult population in 2015, down from 61% in 1971.
The share of U.S. adults living in both upper- and lower-income households rose alongside the declining share in the middle from 1971 to 2015, the share in the upper-income tier grew more.
Over the same period, however, the nation’s aggregate household income has substantially shifted from middle-income to upper-income households, driven by the growing size of the upper-income tier and more rapid gains in income at the top. Fully 49% of U.S. aggregate income went to upper-income households in 2014, up from 29% in 1970. The share accruing to middle-income households was 43% in 2014, down substantially from 62% in 1970.
And middle-income Americans have fallen further behind financially in the new century. In 2014, the median income of these households was 4% less than in 2000. Moreover, because of the housing market crisis and the Great Recession of 2007-09, their median wealth (assets minus debts) fell by 28% from 2001 to 2013.
Meanwhile, the far edges of the income spectrum have shown the most growth. In 2015, 20% of American adults were in the lowest-income tier, up from 16% in 1971. On the opposite side, 9% are in the highest-income tier, more than double the 4% share in 1971. At the same time, the shares of adults in the lower-middle or upper-middle income tiers were nearly unchanged.