pawsplay
Hero
I believe the 1 in 5.
For every game I've seen where the ratio was more like 1 in 3, there's been a game where the ration was 0 in Whatever.
A lot of women are uncomfortable with the male oriented culture of many gaming groups (or flat out find it repulsive, or are actively and intentionally repelled by the gaming group in question). That suggests that when you find female gamers, they may be disproportionately represented in the locale in comparison to the population as a whole.
It could also mean they socially select situations where the 6:0 guys don't encounter them.