I have a little experience with the recording process, having been involved in the production of a contemporary a cappella album, and I think most people wouldn't believe how much stuff is auto-tuned. To my ear, if you listen to something like the Pitch Perfect soundtrack, a lot of it sounds quite obviously pitch corrected, but I will play it to musical friends and they are often surprised when I tell them there's some serious auto-tune going on.

Outside of the a cappella domain, I believe it's pretty prominent in most pop music, but my understanding is that the technology's gotten to the point where 95% of the time you can't tell apart machine correction from good tuning of the vocalist.