In 2012, the State and Homeland Security departments also began a pilot program waiving in-person interviews for visa applicants they deemed low-risk.
China, Brazil and India have fueled demand for temporary visitor permits, the State Department said.
Overall, 66 million tourists visited the U.S. in 2012, generating $168 billion in revenue — up 10 percent from the previous year.
This year could be even better. Through July, the Commerce Department reported a 9 percent jump in tourist spending compared to 2012.