Really? I find that really surprising! I mean, I get the idea a lot of couples break up before uni (due to distance) and if not before, after a few months when the couple realise it doesn't work (with the obvious exceptions). Maybe you're just friends with the a lot of people who like to be in relationships?
I'm not at uni yet, so come to think of it, I can't answer your question, but maybe people are forming relationships to stop themselves from becoming lonely, or they're in a new place and are meeting new people and have just been lucky early on?
Less relevantly I seem to inconveniently be single whenever all my friends aren't and be in a relationship when everyone is off being single. Means double dates have never really been something I've done. :/