Year
These are the present Census Bureau projections for the population of the US to the year 2050. The top line indicates that the population will reach 524 million if fertility rates reach 2.62 children per woman and annual net immigration averages 1,375,000 annually.
The Middle series assumes a fertility rate of 2.15 and net immigration of 880,000 annually.
The lowest series assumes a fertility rate of 1.89 and net immigration of 880,000.
Since at present annual immigration is 1.2 to 1.5 million a year and the fertility rate is 2.1 and increasing due to the large immigrant families, the present estimate for the year 2050 would fall somewhere between the middle and high series, i.e., perhaps about 450 million, an increase of 184 million persons in only about 50 years. But note that the trend is increasing at an increasing rate. Hence, by 2050 we would be adding over 40 million persons a decade.