Recent NPR program
The Trump administration says there is a national security crisis at the Southern border. But most people in the country illegally didn't sneak across the border; they overstayed their visas.
this references data that was published last year from the Department of Homeland Security.
The U.S. Department of Homeland Security (DHS) today released the Fiscal Year (FY) 2017 Entry/Exit Overstay Report. The report provides data on departures and overstays, by country, for foreign visitors to the United States who entered as nonimmigrants through an air or sea Port of Entry (POE) and were expected to depart in FY 2017.