With birth rates projected to remain low, net immigration flows become an increasingly important part of overall U.S. population growth; in 2019, projected net in flows account for approximately 45 percent of overall population growth, but by 2049 that share is nearly 87 percent. CBO projects three broad categories of immigration: legal permanent residents (LPRs), legal temporary residents, and foreign-born people without legal status. In the agency’s projections, the rate of net annual immigration averages 3.1 immigrants per thousand people over the next 30 years, rising from 2.8 in 2019 to 3.1 in 2029 and staying at that level through 2049. That rate, which accounts for all people who enter or leave the United States in a given year, is slightly higher than the average net annual immigration rate since the end of the 2007–2009 recession.
Of those three categories, annual net flows of LPRs are largest, averaging approximately 860,000 people per year in the rst decade and approximately 890,000 annually over the second decade. Net flows of foreign-born people without legal status increase over the next five years in CBO’s projections, from zero net flows in 2019 (meaning that immigration is offset by emigration in this category) to about 170,000 in 2024; thereafter, annual net flows remain about the same through 2039. The annual net increase of legal temporary residents is projected to remain relatively steady, at approximately 80,000 per year, over the next 20 years.
In its projections for years after 2039, CBO uses the same annual rate of growth for all categories of immi- grants. Speci cally, CBO projects that the net number of new immigrants would grow at a rate equal to the growth of the overall population in the previous year; that rate averages 0.4 percent annually through 2049. The share of the population that is foreign born is thus projected to grow from approximately 14 percent today to approximately 16 percent in 2049.