Millennials are on the cusp of surpassing Baby Boomers as the nation’s largest living adult generation, according to population projections from the U.S. Census Bureau. As of July 1, 2016 (the latest date for which population estimates are available), Millennials, whom we define as ages 20 to 35 in 2016, numbered 71 million, and Boomers (ages 52 to 70) numbered 74 million. Millennials are expected to overtake Boomers in population in 2019 as their numbers swell to 73 million and Boomers decline to 72 million. Generation X (ages 36 to 51 in 2016) is projected to pass the Boomers in population by 2028.

The Millennial generation continues to grow as young immigrants expand its ranks. Boomers – whose generation was defined by the boom in U.S. births following World War II – are aging and their numbers shrinking in size as the number of deaths among them exceeds the number of older immigrants arriving in the country.

Because generations are analytical constructs, it takes time for popular and expert consensus to develop as to the precise boundaries that demarcate one generation from another. Pew Research Center has assessed demographic, labor market, attitudinal and behavioral measures and has now established an endpoint – albeit inexact – for the Millennial generation. According to our revised definition, the youngest “Millennial” was born in 1996This post has been updated accordingly (see note below).

Here’s a look at some generational projections:

Millennials

  • With immigration adding more numbers to this group than any other, the Millennial population is projected to peak in 2036 at 76.2 million. Thereafter, the oldest Millennial will be at least 56 years of age and mortality is projected to outweigh net immigration. By 2050 there will be a projected 74.3 million Millennials.

Generation X

  • For a few more years, Gen Xers are projected to remain the “middle child” of generations – caught between two larger generations, the Millennials and the Boomers. Gen Xers were born during a period when Americans were having fewer children than in later decades. When Gen Xers were born, births averaged around 3.4 million per year, compared with the 3.9 million annual rate from 1981 to 1996 when the Millennials were born.
  • Though the oldest Gen Xer was 51 in 2016, the Gen X population is projected to grow for a couple more years. Gen Xers are projected to outnumber Boomers in 2028, when there will be 64.6 million Gen Xers and 63.7 million Boomers. The Census Bureau projects that the Gen X population will peak at 65.8 million in 2018.

Baby Boomers

  • Baby Boomers have always had an outsize presence compared with other generations. They peaked at 78.8 million in 1999 and have remained the largest living adult generation.
  • There were an estimated 74.1 million Boomers in 2016. By midcentury, the Boomer population is projected to dwindle to 16.6 million.

Note: This post was originally published on Jan. 16, 2015. It was updated April 25, 2016, under the headline “Millennials overtake Baby Boomers as America’s largest generation,” which reflected the Center’s definition of Millennials at the time (born between 1981 and 1997). This third version reflects the Center’s newly revised definition, under which Millennial births end in 1996.