Stopping just a tiny percentage of illegal immigrants surging into the United States would pay for President Trump’s wall by eliminating the lifetime taxpayer costs provided to those aliens, according to a detailed financial analysis.

The Center for Immigration Studies, which advocates for lower levels of immigration, said that the border wall between Mexico and the United States would only have to stop 3 percent to 4 percent of potential illegal crossers, or about 60,000 of an estimated 2 million over the next decade, to pay for Trump’s $5 billion request.