An anonymous reader writes: The United States' slice of the international tourism pie is declining, according to a new report from Foursquare that looks at data from millions of phones worldwide. The US share of international tourism dropped 16% in March 2017 compared with the previous year. And it declined an average of 11% year over year in months spanning October 2016 to March 2017, according to the report. The drop coincides with the final month of the US election, the Trump transition, and the early months of the Trump administration, which notably imposed a travel ban on people from several majority-Muslim countries in January 2017 that was eventually halted in court but is currently under appeal. Declines in tourism market share from people originating in the Middle East were more pronounced than the rest of the world, down 25% this January, along with a smaller decrease from South America, Foursquare found. The data accounts for the percentage of international tourism coming to the US and not the absolute number of tourists, but Foursquare CEO Jeff Glueck told BuzzFeed News that it's unlikely tourist visits to the US increased while share declined. "I don't think you'd see a 16% decline in international market share and absolute numbers being up. I don't think that's compatible," he said. "The volume of tourism doesn't change that fast."