This graphic shows where America’s most-skilled foreign workers are coming from

Every year, the United States lets in about 65,000 of the world's most-skilled workers.

The visas, referred to as H1-B, are highly competitive. They're so competitive that in the last two years, the acceptance cap was reached within a week of the applications becoming available. They can also be valuable. Entire scams have arisen in India to make money from them.

What exactly is an H-1B visa and who’s using them?

The State Department defines the H1-B as a non-immigrant visa for a foreign person working in a specialty occupation. The H1-B requires “a higher education degree or its equivalent.” Every skill-based career is included in this visa category, from fashion designers to military contractors.

It’s designed to allow American companies to hire employees that have skills that they cannot find within the US population. Last year, the United States Citizenship and Immigration Services (USCIS) approved more than 150,000 H-1B visas for foreign workers.

Where are they working?

Using data from the State Department, the chart below shows you the top 10 occupations for H1-B visas.

Most work in the IT industry. Brookings Institute senior analyst Neil Ruiz said most H1-B visas go to people working in a Science, Technology, Engineering, and Mathematics (or STEM) field.

Some experts think the emphasis of H-1B visa distribution within the math and sciences industries is due to the “American STEM shortage.” Fewer Americans are choosing to work in STEM fields, or they just aren’t qualified for the jobs, and skilled foreign workers are there to fill the demand.

Where are they coming from and where are they going?

For almost two decades now, the US government has given Indians the most H1-B visas. By far.

“India has a competitive advantage in the global IT industry,” Ruiz said. Companies like IBM will hire Indian IT firms that act like consultancy firms for technology. The business model of these companies is to do client-based work, working on individual projects for a short-term basis. “For example, Walmart hired three IT firms to help standardize all of their outlets on a global scale. It’s not just about there being a STEM shortage in America. There’s a different set of skills these [Indian] companies bring for [American companies] looking for IT consulting.”

According research by Ron Hira of the Rochester Institute of Technology, four of these types of Indian IT companies — Cognizant, Infosys, Tata Consultancy Services and Wipro — brought more than 26,000 Indians to work in the US in 2012 under the H-1B visa. All four are also on the list of top 10 employers of H-1B workers this year:

With all of this emphasis on IT work, it’s unsurprising that the state with the most H-1B visas every year is California, home to Silicon Valley.

Ruiz has also conducted research that looks at H-1B visas at the metropolitan level. His work found that different cities have pockets of H-1B visa holders that work in the same industry, “Cities like New York and Bridgeport, Connecticut are known for hiring foreign workers in investment banking and consulting,” Ruiz said. Wall Street’s affinity for foreign hires could contribute to New York being the state with the second highest number of H-1B visas every year.