Vacations have long gone hand-in-hand with company: family bonding, honeymoons, babymoons, bands of oats-sowing college backpackers. Yet today, more and more travelers are going solo — and they’re not who you might expect them to be.

Some 24 percent of people traveled alone on their most recent overseas leisure vacation, up from 15 percent in 2013, according to the 2015 Visa Global Travel Intentions Study, which was conducted across 25 countries by Millward Brown, a market research organization. Among first-time travelers, solo travel is even more popular, jumping to 37 percent, up from 16 percent in 2013. And while the stereotypical solo traveler has traditionally been single and looking, a solo traveler these days is just as likely, if not more likely, to be married or in a committed relationship.

As the numbers creep up, more travel brands are paying attention. Take Solos Holidays, one of the oldest and largest companies in Britain offering guided getaways for solo travelers. The company has been around since 1982, but a few weeks ago it introduced an American arm, Solos Vacations, that’s beginning to offer escorted trips (to Italy and Britain so far) through Solosvacations.com. (Guided tours in general are becoming more popular among solo travelers, according to Visa’s research, up almost threefold compared with 2013.)

Who exactly are these solo travelers?

Many are unattached, of course. “I was amazed to find that over half of American adults are single,” said Andrew Williams, the managing director of Solos Holidays. He was referring to research about the percentage of American adults who have never been married being at a historic high. (In 2012 one-in-five adults (25 and older) had never been married, according to analysis of census data by Pew Research Center, compared with about one-in-ten adults in 1960.) “It’s clearly a shift in the same direction that we’ve seen in the U.K.,” he added. “Perhaps you’re a little further ahead than we are in that regard.”