In response to the twin notions that sexual assaults are a) increasing and b) particularly prevalent on college campuses where a "rape culture" supposedly exists, comes this recent report from the DOJ on sexual assault prevalence among college aged women.
Update: For a university the size of UVA (20,000 students, presumably 10,000 women) these data imply about 200 of the current students will be sexually assaulted over their four years. This is a depressingly large number, and makes one wonder with this many examples to choose from how Rolling Stone managed to find one case that was so obviously heavily embellished (at a minimum) or fraudulent. 200 is, however, an order of magnitude smaller than the 2000 that would be predicted by the "1 in 5" number which is repeated so uncritically by public figures.
As to the declining trend, I understand the issue of under-reporting, though most folks in the know seem to think this type of study (which includes unreported cases) is more accurate than reported crime figures. But for under-reporting to affect the trend (rather than the absolute numbers) one would have to argue that the reporting percentage is declining, something for which I have never seen evidence and which is a proposition that defies common sense. Over the last decades, sexual assault victims have gone from being shamed to being protected to being put on a pedestal (given our current fetishization of victimization). It is hard in this environment to imagine sexual assault reporting rates going down.