Well, I'm not sure what 'sexual assault' means anymore, to be honest, so I don't know what to make of those figures.  In Canada, the criminal code for sexual assault covers everything from the seriously nasty assaults to some drunken jerk in a bar giving you a pinch as you walk by.   When people talk about 1 out of 5 (or 4) women having been assaulted in their lifetime, that's what they mean and why the number is so high. 

Based on that, pretty well every woman I know, and myself, have been the victims of sexual assault, whether we characterized it as that or not.