U.S. Sen. Marco Rubio supports President Donald Trump's promise to build a wall at the Mexican border, but he said it won't address the main path that undocumented immigrants use to arrive in Florida.
"In Florida, 70 percent of the people here illegally came on an airplane," Rubio, a Florida Republican, told reporters Jan. 27 while visiting growers in Immokalee. "They overstayed a visa — the wall isn't going to address that."
Rubio is one of many politicians to raise concerns about immigrants overstaying their visas. In 2015, he said nationally, 40 percent of illegal immigrants had overstayed a visa, a claim we rated Mostly True. But is the rate 70 percent in Florida?
We found no comprehensive data from the federal government to back up Rubio's point, and his spokespersons didn't respond. However, a longtime researcher about the undocumented population came up with an estimate for Florida that was close to 70 percent.
Although there are legislative requirements to track nonimmigrants' entry into and exit from the United States, the federal government has struggled to accurately count visa overstays.
What we know is based on either recent incomplete federal data or older data and estimates.
Last year, the Department of Homeland Security estimated that out of 45 million U.S. arrivals by air and sea whose tourist or business visas expired in fiscal year 2015, about 416,500 people remained in the country in 2016.
However, that data only covers a small slice of the undocumented population, capturing one year of data and omitting people who arrived via land. Also, the report did not provide a breakdown by state.
In 2006, the Pew Research Center estimated that as much as 45 percent of the unauthorized population entered the country with temporary visas. That report relied on a 1997 study from the Immigration and Naturalization Service.
Other estimates of overstays are also a bit dated: In January 2003, an INS report said 33 percent of the illegal immigrant population in 2000 had entered the country legally. A 2004 report from the General Accounting Office, based on 2000 data, estimated visa overstays ranged from 27 to 57 percent.
Robert Warren, a former INS demographer whose work was part of the 1997 INS report, said that in recent years relatively more immigrants have overstayed their visas than have "entered without inspection."
The percentage of undocumented immigrants coming from Mexico dropped significantly in the past 15 years — and that's a key country for the group of immigrants who cross the border illegally without a visa.
Warren, a fellow at the nonpartisan Center for Migration Studies, did some calculations for PolitiFact Florida.
He used the Center for Migration Studies' estimates of the undocumented population in 2014, based on census data. Those estimates show about 10.9 million undocumented immigrants living in the United States, including 710,000 in Florida.
Then Warren examined the number of undocumented immigrants from 148 countries living in the United States and in Florida. He made some assumptions about what percentage of undocumented immigrants overstayed their visa compared with those who slipped through the border.
For example, he estimated that 15 percent of undocumented Mexicans were visa overstayers, compared to 75 percent from the Dominican Republic.
Using those assumptions, he concluded that in Florida, an estimated 430,000 of 710,000 undocumented immigrants — 61 percent — overstayed their visa.
It's not a surprise that Florida's undocumented immigrant population would include a higher percentage of visa overstayers than the national average.
While most people crossing the border illegally come from a few countries including Mexico, undocumented immigrants who come from countries in South America, Asia or Europe are nearly all visa overstayers, he said.
"What it comes down to is Florida has a higher mix of people who don't come from Mexico or Central America than the country as a whole," he said.
However, Warren said the percentage of visa overstayers in Florida probably would be higher if you just looked at arrivals in the past 10 years.
"To make estimates in this area of research you must make some assumptions based on the best information you have — that is what I have done here," he said.
We ran Warren's estimate by other immigration experts, including Jeffrey Passel at the Pew Research Center, a nonpartisan "fact tank" that doesn't take policy positions, and Jessica Vaughan from the Center for Immigration Studies, which advocates for low levels of immigration.
Both Passel and Vaughan said Warren's estimates were reasonable. Vaughan did note, however, that his starting point for the size of the undocumented population is lower than Pew's 2014 estimate.
For an on-track claim that requires more information, we rate Rubio's statement Mostly True.
Read more at PolitiFact.com/Florida.