For the 30 years between 2024 and 2054, the Congressional Budget Office predicts: Population growth generally slows over the next 30 years, from 0.6 percent per year, on average, between 2024 and 2034 to 0.2 percent per year, on average, between 2045 and 2054. Net immigration increasingly drives population growth and accounts for all population growth beginning in 2040, in part because fertility rates remain below the rate that would be required for a generation to replace itself in the absence of immigration.
This projection accounts only for foreign-born persons coming to the U.S. It does not take account that these foreign born persons are more likely than the U.S.born population to be of child bearing age. Hence their offspring – 2nd generation immigration contribute relatively more to population growth.