From the Pew Research Center:
For most of the past half-century, adults in the U.S. Baby Boom generation – those born after World War II and before 1965 – have been the main driver of the nation’s expanding workforce. But as this large generation heads into retirement, the increase in the potential labor force will slow markedly, and immigrants will play the primary role in the future growth of the working-age population (though they will remain a minority of it). The number of adults in the prime working ages of 25 to 64 – 173.2 million in 2015 – will rise to 183.2 million in 2035, according to Pew Research Center projections. That total growth of 10 million over two decades will be lower than the total in any singledecade since the Baby Boomers began pouring into the workforce in the 1960s. The growth rate of working-age adults will also be markedly reduced. The largest segment of working-age adults – those born in the U.S. whose parents also were born in the U.S. – is projected to decline from 2015 to 2035, both in numbers and as a share of the working-age population. The Center’s projections show a reduction of 8.2 million of these adults, from 128.3 million in 2015 to 120.1 million in 2035. That numerical loss will be partially offset by an increase in the number of working-age U.S.-born adults with immigrant parents, who are projected to number 24.6 million in 2035, up from 11.1 million in 2015. But perhaps the most important component of the growth in the working-age population over the next two decades will be the arrival of future immigrants. The number of working-age immigrants is projected to increase from 33.9 million in 2015 to 38.5 million by 2035, with new immigrant arrivals accounting for all of that gain. (The number of current immigrants of working age is projected to decline as some will turn 65, while others are projected to leave the country or die.) Without these new arrivals, the number of immigrants of working age would decline by 17.6 million by 2035, as would the total projected U.S. working-age population, which would fall to 165.6 million.