I am nearly 100% certain that none of my friends I had growing up was sexually abused. We all lived in the same street, went to the same school, I knew their parents well. We saw each other every single day. There was no abuse going on.
As for my friends I have made as an adult, at university, I would be so, so surprised if any of them had been sexually abused either. It is a subject that we have talked about (commenting on stories of abuse in the media for example) and they have all, like me expressed utter horror that anyone could do such things to a child. They (like me) find it hard to imagine because it is so far removed from their own experiences growing up.
I find it sad that people can believe that the majority of children in our society are abused before they are 12 years old.:
The insidious nature of abuse is that it isn't readily apparent to outside observers. I grew up with a girl who, by all accounts, was "normal" and it wasn't until years and years had gone by that we learned that her father was sexually abusing her and her sister. And it doesn't sound to me like any of your friends had any substantial conversations about abuse. I've known plenty of women who, in some circles will express profound disbelief, but later admit their own experience.