But these surveys don't distinguish the two cases.
It's the usual pattern: Identify a real issue. Do everything you can to inflate the numbers to make people take the problem more seriously. Often this is followed by finding solutions to those inflated numbers and crowing about success--while the original problem remains untouched.
The actual result is that it backfires as people see the cases in those inflated numbers and realize they're crap.
Couple of points: That 15% is the lowest figure I've ever seen, and I've been following the issue since I was in college a million years ago.
You also seem to insist that the survey authors don't know what they are talking about because you don't know what they're talking about and because you don't like the results. You have decided that the authors of the survey were not precise because YOU don't like the results.
Your refusal to engage in honest discourse about the issues of rape backfire. Only fellow misogynists believe that the numbers are inflated. And no where, never is there a single suggestion that perhaps men could change some of their behavior, that society should change some norms to reduce the incidence of sexual assault.