For all the political rigmarole about restricting visitors to the U.S. from countries such as Syria and Iran, a report from the Department of Homeland Security indicates that Canadians are the most likely visitors to remain in the U.S. after their visa expires.

Overall, 527,127 foreign visitors overstayed their visa in the 2015 fiscal year out of 44,928,381 total admitted visitors. This means that 1.17 percent of foreign visitors to the U.S. who entered without an immigrant visa overstayed in the U.S.

The worst culprits by far were Canada and Mexico, which combined for 145,178 total overstays, more than a quarter of those who didn’t leave the U.S. after visa expiration. The numbers in the report don’t even include land entries from both U.S. neighbors, meaning the actual numbers are probably much higher.

The report indicates how difficult it is for Homeland Security to account for all foreign travelers who enter the U.S.

“The process of matching data to determine overstays has been extremely difficult, as the data collection processes for arrival and departure information are not the same,” writes Homeland Security. “The United States did not build its border, aviation, and immigration infrastructure with exit processing in mind. Despite these significant challenges, in recent years, the Department has made substantial improvements to enhance its capability to record arrivals and departures from the United States, detect overstays, and interdict threats.”

A look at the data shows that overstay percentages are misleading, because the countries with the highest rate of overstay have a tiny number of overall visitors.

Djibouti, for instance, had the highest overstay rate of any country with 27.67 percent of Djiboutians overstaying their visa. But only 96 total travelers overstayed.

Here’s a breakdown of the top ten countries.

CountryTotal FY2015 overstays
Canada99,906
Mexico45,272
Brazil36,991
Germany22,554
Italy18,997
U.K.18,950
China18,246
Colombia17,155
India14,348
Venezuela12,729
Photo Credit: Kevin Molloy, VP Simplified Passenger Travel, Vancouver Airport Authority, (right) and John Wagner, Acting Deputy Assistant Commissioner, US Customs and Border Protection (centre), assist one of the first US passengers using the newly launched Automated Passport Control kiosk at Vancouver International Airport, Richmond, BC, Tuesday, May 7, 2013. U.S. Customs and Border Protection