Foreign-born nearly doubled share of STEM workers since 1990

The number of foreign-born workers in STEM fields — science, technology, engineering and math — in the U.S. workforce has increased dramatically in the past 25 years, according to the American Immigration Council. In 2015, foreign-born workers comprised nearly a quarter of the total STEM workforce, up from 11.9% in 1990.

Why it matters: Workers in with expertise in these technical areas are in extremely high demand in the U.S., with many companies unable to find enough workers with so-called STEM skills to fill open jobs. U.S. schools aren't graduating enough workers with STEM skills to meet the high demand.

Visa questions: Many big firms, especially tech companies, have at least partially filled that gap with H-1B visas to bring in technical talent from abroad — but the Trump administration has proposed initiatives to restrict some access to that program for some job categories. The administration is also trying to expand public-private apprenticeship programs to create a stronger pipeline of technical skills that companies are desperate to hire.

These numbers are based on 46 STEM occupations, as defined by the Commerce Department, that are classified into four different categories — computer and mathematics, engineering and surveying, physical and life sciences, and managerial. It doesn't include health and social sciences jobs. In 1990, foreign-born workers made up 11.9% of the STEM workforce, which increased to 24.3% in 2015.

Beyond labor: Foreign STEM workers aren't just needed to fill jobs in the fast-growing technology industry, they are also seen as major contributors. They receive rising shares of U.S. patents in computing, electronics, medical devices and pharmaceuticals. And 40% of companies in the Fortune 500 in 2010 were founded by an immigrant of the child of an immigrant.

Top jobs: Software engineering is by far the largest occupation with high percentage of foreign-born workers, which made up 39% of that category in 2015. These workers are also prominent in nuclear and electrical engineering, the report showed.

Top states: Unsurprisingly, California has by far the highest number of foreign-born STEM workers, with just over 492,000. New York came in second with 121,000.