I think there’s a lot more of a tendency for women to use the bi label even when they aren’t that serious about it and aren’t really sure, just because it’s trendy. Whereas guys usually would prefer to be 110% sure before calling themselves bi because obviously the social risk is greater. But as for how many women are actually, genuinely bi, I don’t think the number is much if any higher than that for men.
I’m bi and I can’t tell you how many of these “I might sleep with a girl once when I’m drunk but I would NEVER DATE a woman” or “she can eat me out but I’m not reciprocating” kind of pillow princess hetero women who call themselves bi... pretty much just cause they can. Can not tell you how frustrating it is.