We've often heard it said that very few Americans (10%?) bother to get passports. That claim is often made within the context of a theory that citizens of the U.S.A. are isolationist or incurious about the world around them. It's rarely flattering.
It was doubly intriguing to read here not only that somewhere around 30% of Americans hold passports, but that the per capita number of passport holders varies greatly from state to state.
Now that they're required even to enter Canada - unless one holds, say, an enhanced driver's license - it's not hard to imagine that residents of most border states will join those in Washington to obtain them.
It should be a real money-maker for the federal government.