U.S. Citizenship and Immigration Services (USCIS) released a wealth of information about the H-1B and L-1 temporary visa programs for professional talent, revealing trends about the programs, which employers are using the visas, and the demographics of visa recipients.

The data from USCIS included a 10-year look back at petition filings for H-1B visas for skilled workers in positions requiring specialized knowledge. The H-1B program has a cap of 85,000 visas per year, including 20,000 specifically for recipients of advanced degrees. In addition, universities, research institutions and government agencies can sponsor an unlimited number of H-1B workers, who are exempt from the cap.

The agency also released data on approved L-1 petitions for fiscal years (FYs) 2015-2016.

L-1A visas allow U.S. multinational companies to transfer managers or executives from a foreign office to a U.S. location, while L-1B visas allow a company to transfer an employee with “specialized knowledge” from a foreign office to the U.S. There is no yearly cap for these visas.

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Here are three main takeaways from the USCIS data:

Demand Trending Up, 2017 Approvals Are Down

Organizations applied for approximately 3.4 million H-1B workers over FYs 2007-2017, of which 77.5 percent, or 2.6 million were approved. Over 336,000 petitions were submitted in FY 2017, more than any year in the last decade except for FYs 2015 (369,000) and 2016 (399,000), the leading years for both H-1B visa petitions and approvals.

Throughout that period, applications rose steadily, except for downward turns during the height of the Great Recession in FYs 2008 and 2009, again in FY 2013 and in FY 2017—President Donald Trump’s first year in office. The number of approvals largely rose and fell in correlation with the number of applications, until the significant decline from FY 2016 to FY 2017, when just 59 percent were given the green light. The prior lowest approval rate over the past decade was 74 percent in FY 2010.

“In April, President Trump issued an executive order directing a review of the H-1B program, particularly on its effect on American wages and jobs,” said Preston Huennekens, a research assistant at the Center for Immigration Studies, a Washington, D.C.-based think tank and research organization. “The program has become incredibly popular in recent years with the explosion of growth in the tech industry. Silicon Valley giants such as Google, Facebook and Apple have relied on H-1B workers for years, and these foreign workers make up a significant percentage of their workforce.”

The L-visa category has also been slowly, but steadily, growing. In FY 2016, over 79,000 L-1 visas were in use, up from 78,500 in FY 2015. USCIS approved at least 26,000 new L-1 petitions in FY 2016, a 2.2 percent increase from the 25,500 new petitions approved in FY 2015.

Tech Firms, IT Suppliers Are Biggest Users

Technology-related industries make up most of the companies that petition for H-1B and L-1 workers. About 60 percent of H-1B visas were awarded to workers in computer-related occupations over the last decade. “Given the widespread use of the H-1B visa in Silicon Valley and tech-related industries in general, it is not surprising that the majority of petitions are in the computer science and engineering field,” Huennekens said.

While the majority of H-1B workers are employed throughout the tech industry, the leading H-1B and L-1 employers are foreign-based IT staffing and consulting firms.

Indian companies Infosys Limited, Tata Consultancy Services, Wipro Limited and IBM India have been granted the lion’s share of H-1B visas over the last several years. Tata has also been one of the biggest users of the L-1 program in the past two fiscal years. Seven of the top 10 companies that petitioned for L-visas are headquartered outside of the United States.

Recently released data also provides hard numbers on the salaries of H-1B workers. Compensation has risen 26 percent since 2007, from an average annual wage of $68,159 to $92,317. The median grew by a similar amount from $60,000 to $83,230. Notably, the IT outsourcing companies that receive the most visas on average paid much lower salaries to their workers than H-1B workers hired directly by U.S.-based employers like Apple, Google, Amazon and Microsoft.

Visas Mostly Go to Indian Millennials

Most H-1B and L-1 visa filings are for Indian nationals, who account for 64 percent of all H-1B filings since 2007. China is next with 9 percent of all filings, followed by the Philippines, South Korea, Canada and Taiwan with much lower totals. However, the number of H-1B visa petitions for Indian nationals in FY 2017 actually declined for the first time in seven years.

“In the future, many will be curious to see whether China and India continue to dominate the program or if other rapidly developing countries will begin to file more petitions,” Huennekens said.

The majority of H-1B visas (69 percent) go to individuals ages 25-34, followed by workers ages 35-44 (22 percent.) Most H-1B employees have at least a bachelor’s degree, and the majority hold master’s degrees.