As much as we focus on sexism in American culture, we take for granted how much better off women here are than in many other countries. Japan has a highly sexist culture, and the huge population density leads to cramped, uncomfortable public transportation. I'm sure there are many lecherous men who use that claustrophobic environment to grope unsuspecting women, but I'm also sure unintentional contact has been misconstrued as groping. I'd imagine the figure is high, but not quite 70%.
My idea of Japanese people is that they are orderly and polite, so this statistics are surprising to me. On the other hand, knowing how crowded public transit is in big cities such as Tokyo, I can see how this kind of incident would happen very often. Overall, I find 70% to be an overly high number, and that is why I was surprised by it, despite the circumstances in the city.
People are perverts, it doesn't matter what country they are from. This does not suprise me at all. I'm willing to be that America has an even higher rate of this type of thing happening. I wouldn't be suprised if worse things happen on the train in America. Not cool.
Ask any woman who has ever travelled on a crowded train or metro if she has ever harassed or "groped." I'm guessing most women will nod furiously, and roll their eyes. Although I find it extremely depressing, I'm not one bit surprised that 70% of female high school students in Tokyo have been harassed in this way.