Data for the 1900 to 2007 period can be found here.[1]
Data from 2008-present is available from the Federal Reserve Economic Data.[2]
Note: The chart shows the foreign born in the civilian non-institutional population (age 16+ non-institutionalized), not the total population. The number and rate is lower than the total number of foreign born in the overall population. The civilian non-institutional population is used in computing employment statistics like the unemployment rate.