Millennials now outnumber baby boomers as the biggest age group in the United States, the US Census Bureau said Thursday in its latest population estimates.
Americans born between 1982 and 2000 currently number 83.1 million, or more than a quarter of the total population, it said.
Millennials are also an ethnically more diverse bunch, with 44.2 percent being African American, Hispanic, Asian or belonging to some other non-white group.
In another first, a majority -- 50.2 percent -- of Americans under the age of five belong to a minority race or ethnic group.
The Census Bureau, a federal government agency, puts the estimated total US population as of Thursday at just over 321 million.
It defines baby boomers as Americans born in the aftermath of World War II between 1946 and 1964 -- a group now entering their post-65 retirement years.
Overall, America "has become more racially and ethnically diverse," with minorities making up 37.9 percent of the population in 2014, up from 32.9 percent a decade earlier.
Minority groups were in the majority in Hawaii, the District of Columbia, California, New Mexico and Texas, with Nevada close to joining the pack.