This is just statistics, statistics lies a lot, my friend. Just imagine how they calculated al those figures. They select a pool of different categories of people ideally in different geographical locations and just imagine how many people would confess: "I have just masturbated and then I shaked my friends hand with my hand unwashed...":) Of course sociologists would admit that say there is +/- 15% (of a different figure) of lies in the answer and would deduct or add, but that 15% figure is also a fake figure just a supposition....so, I am continuing my breakfast :)!