How is probably a more important question than how many.
Met a girl once who told me that her friend would meet people in the university library and ask "have we shagged" and then went off to the toilets, she then had a breakdown and started having sex in the middle of shopping centres when on supervised leave from MH wards.
I would be more put off by the lack of any serious discrimination when she picks partners than the actual number.
Why do people keep counting anyway? I stopped when it was over 30. It doesn't matter. Last weekend I went for a swim, I didn't feel much point counting lengths either.