One factor behind the substantial growth among younger adults is their use of mobile dating apps.
The protocols and practices of dating, and the terms used to describe it, vary considerably from country to country and over time.
While the term has several meanings, the most frequent usage refers to two people exploring whether they are romantically or sexually compatible by participating in dates with the other.
With the use of modern technology, people can date via telephone or computer or meet in person.
Dating may also involve two or more people who have already decided that they share romantic or sexual feelings toward each other.
But it still means that one-third of online daters have not yet met up in real life with someone they initially found on an online dating site.