While that low figure is often quoted to reinforce the notion that Americans are insular stay-at-homes with a blinkered view of the world, it's a myth.
You'd have to go back to 1994 to find that only one in 10 Americans held a passport.
Today the figure is close to 45 per cent, and the percentage has been rising steadily.
According to the US State Department, there were 146.8 million valid US passports in the year ending September 30, 2019, a rise of nine million over the previous year.
One reason for the increase is that until a decade ago, US citizens could travel to Canada and Mexico without a passport.
However the rules changed in 2007 and that led to a 50 per cent increase in the number of passports issued that fiscal year.
Another factor – travel to Europe in particular has become far cheaper with the rise of low-cost carriers on the transatlantic route, spurring the appetite for foreign places.
By comparison, 57 per cent of Australia's population hold a current Australian passport.