Now, more than half of Americans are millennials or younger

A new analysis by the Brookings Institution shows that 50.7% of U.S. residents were under age 40, as of July 2019.

There are now more young Americans than older Americans, as millennials and younger generations now make up a majority of the U.S. population.

About 50.7% of U.S. residents were under age 40, as of July 2019, according to a new analysis by the Brookings Institution.


The combined millennial, Generation Z and younger generations are about 166 million people, according to the Brookings’ analysis of population estimates released this summer by the U.S. Census Bureau. The combined Generation X, baby boomer, and older cohorts represented 162 million U.S. residents.

Millennials typically are defined as being born between 1981 and 1996. Baby boomers, long considered a primary driver of demographic and social change in the United States because of their large numbers, were born between the end of World War II and the 1964 arrival of the Beatles in the U.S.

Squeezed between the boomers and millennials, Generation Xers were born in the late 1960s and 1970s. Members of Generation Z were born after 1996.


“To many Americans — especially baby boomers — this news may come as a shock. For them, the term “millennial” has been associated with a youthful, often negative, vibe in terms of habits, ideology, and politics,” William Frey, a senior fellow at Brookings’ Metropolitan Policy Program, wrote in the analysis. “Now, the oldest millennial is 39, and with their numbers exceeding those of baby boomers, the millennial generation is poised to take over influential roles in business and government.”

Those under 40 are more diverse than the older cohorts, with almost half identifying as being part of a racial or ethnic minority. Past surveys show that the younger generations split from the older generations on issues such as immigration reform, criminal justice reform and environmental protection, and the coronavirus pandemic and recent racial justice protests are likely to galvanize the younger groups to promote an array of progressive causes, Frey wrote.

The Associated Press contributed to this report.