Americans are among the least likely to have travel abroad, according to a study by a British relocation firm.

The firm MoveHub, using data from the World Bank and the World Tourism Organization, says U.S. citizens on a per capita basis made only 0.2 international trips a year. That compares with 11.4 international trips a year for Hong Kong residents.

Overall, the United States ranked 60th of more than 100 nations in the study for international travel, despite having the world’s biggest economy in 2016. In terms of money spent while traveling abroad, Americans ranked 33rd.

The British firm, which noted that fewer than half of U.S. citizens hold passports, suggested that Americans might be less likely to take international trips because in general they are allotted less paid vacation time than people in other countries.

A 2013 report by the Center for Economic and Policy Research, for example, found that the United States was the only country among a group of wealthy nations — that included Australia, Canada, Japan, New Zealand and 16 European nations — that did not require employers to grant their workers paid vacation. (Imagine: Five countries required employers to pay their workers a small vacation bonus to help defray vacation-related expenses, the report found.)

What’s more, only a third of Americans use the vacation time allotted to them, according to a January 2016 survey done by British Airways.

In Hong Kong, by contrast, people receive paid vacation leave and 12 bank holidays a year in which to use it, MoveHub says. The other top 10 include Luxembourg, Hungary, Sweden, Finland, Ireland, Singapore, Switzerland, Denmark and Albania.  The data covered the years from 2007 to 2016.

Of course, it’s also easier for Europeans to visit another European country than it is for an American to get there. Americans might also like staying home because there’s a lot of it to see, and gas prices have been relatively cheap the past three years. AAA has reported strong demand for highway travel this year, particularly around the holidays, with more people hitting the road for the Fourth of July than ever and the heaviest Memorial Day traffic since 2005. And the travel group just reported that the price of a gallon of gas is trending downward yet again, following increases related to the impact from Hurricane Harvey on the nation’s refining industry.

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