So I went back through our 12 games last season. We had 60 kickoffs.
3 went OOB
1 went for a TD
4 were fair caught
8 were touchbacks
So only 20% (12 out of 60) of our kickoffs were placed at the 25. So, one conclusion I have is that we fair catch way more of the kickoffs that come to us than what other teams are choosing to fair catch. Also, other teams are better at putting the ball into the end zone on the kickoff than what we did.
I would tend to agree with Statefan, this almost has to be by design. Our coaches want our kickoffs to be returned. 80% of our kicks were either returned or went out of bounds before they could be returned. That has to be one of the higher percentages of returnable kicks in college football last year, and I can't imagine we did it by chance alone.