One thing often forgotten in the run-up to a tense Election Day: There are an estimated 8 million non-military Americans living and working around the world. Their vote never gets included on FiveThirtyEight.com and other polling aggregators, because it's incredibly hard to poll them.

But if a new survey of expats conducted by money transfer company TransferWise is any guide, expats are unusually engaged with this election. Some 95% of them plan on mailing their vote in — and nearly 85% of them are voting for Hillary Clinton. Less than 5% plan on voting for Donald Trump.

If that's an accurate reflection of the expat population at large, it means Americans abroad could provide enough votes to tip close states such as Florida, Ohio and North Carolina in Clinton's direction. (In the survey, Trump has his best chance with expats from Florida, nearly 15% of whom plan to vote for him.)

That's a big if, of course. TransferWise polled its customers, and some 508 opted in — statistically significant enough for a poll in itself, but drawn from a pool of people who send money back to the U.S. Still, the company has verified the U.S. citizenship and foreign addresses of all respondents.

Outside the U.S., every poll of global sentiment has suggested that most countries would vote for Clinton in large numbers. Just last week respondents in one poll of 3,500 people in Canada, France, Germany, Russia, Mexico and the UK went for Clinton by 60% to 40%. Only Russian voters preferred Trump, 48% to 15%.

Some 55% of the new survey's respondents said that living abroad had swayed their vote.

In the 2012 election, a mere 15% of Americans living abroad actually mailed their votes in, a typically disengaged number. Nevertheless, mail-in ballots from expats have been credited with tipping tight Congressional elections before — such as the 2008 Minnesota Senate race that went to Democrat Al Franken by 312 votes.

Another survey of 1,800 Americans living abroad, back in June, also saw engagement levels rising. An expat tax services company called Greenback teamed up with various expat support groups, and found 73% of respondents intended to vote in the 2016 election — up from 57% who said the same in 2015.