Owners of businesses that cater to immigrants are watching their sales dry up as customers stay home, fearing deportation should they venture out into public.

President Donald Trump pledged to deport up to 11 million undocumented immigrants during the campaign and has since changed U.S. immigration policy to broaden the number of undocumented immigrants eligible for deportation, the Wall Street Journal reports. Trump also called for hiring more immigration enforcement officers to help with the crackdown, and business owners across the country who rely on undocumented customers said their profits have been devastated.

While it is hard to estimate the economic activity driven by the nation’s 11 million undocumented immigrants, a report last year from the Institute on Taxation and Economic Policy said America’s undocumented immigrants pay around $11.6B in taxes each year. That is nothing compared to the $4.7 trillion reduction to U.S. gross domestic product that would occur over the course of 10 years should 11 million undocumented immigrants leave the country.