NEW YORK—The middle class, once the economic stratum of a clear majority of American adults, has steadily contracted in the past five decades. The share of adults who live in middle-class households fell from 61 percent in 1971 to 50 percent in 2021, according to a new Pew Research Center analysis of government data.

The shrinking of the middle class has been accompanied by an increase in the share of adults in the upper-income tier–from 14 percent in 1971 to 21 percent in 2021–as well as an increase in the share who are in the lower-income tier, from 25 percent to 29 percent. These changes have occurred gradually, as the share of adults in the middle class decreased in each decade from 1971 to 2011, but then held steady through 2021, according to the Pew Research report. 

The organization’s analysis presents seven facts about how the economic status of the U.S. middle class and that of America’s major demographic groups have changed since 1971. 

Among the findings noted in the Pew report: Household incomes have risen considerably since 1970, but those of middle-class households have not climbed nearly as much as those of upper-income households. The median income of middle-class households in 2020 was 50 percent greater than in 1970 ($90,131 vs. $59,934), as measured in 2020 dollars. These gains were realized slowly, but for the most part steadily, with the exception of the period from 2000 to 2010, the so-called “lost decade,” when incomes fell across the board.

In addition, the median income for lower-income households grew more slowly than that of middle-class households, increasing from $20,604 in 1970 to $29,963 in 2020, or 45 percent.

The rise in income from 1970 to 2020 was steepest for upper-income households. Their median income increased 69 percent during that time, from $130,008 to $219,572, according to the Pew analysis.

As a result of these changes, the gap in the incomes of upper-income and other households also increased. In 2020, the median income of upper-income households was 7.3 times that of lower-income households, up from 6.3 in 1970. The median income of upper-income households was 2.4 times that of middle-income households in 2020, up from 2.2 in 1970.

The Pew Research Center analysis and the “seven facts about how the economic status of the U.S. middle class and that of America’s major demographic groups have changed since 1971,” can be read here.