Based on the Bureau of Labor Statistics definition of STEM fields, generally including jobs in science, technology, engineering, math, health and social sciences, foreign-born workers comprised about 19% of the sector's workforce when it was last measured, in 2015. In 2019, the BLS reported that immigrants to the U.S. made up about 17% of the country's total workforce.
Data from the Census Bureau excludes health and social science, resulting in a higher estimate for the foreign-born population in the STEM workforce of about 22%. The narrower census definition results in a STEM workforce of 8.1 million workers, about 5% of the total U.S. workforce in 2015. The wider classification including health fields expands the population to 20.4 million, 12.6% of the workforce.