I can't recall a gaming group that didn't have at least one, usually two or more females in recent times. Sure 25 years ago it was different, but now... many women play in my gaming groups. I had a 4E home game that was 4 females and 2 males.
I'm not sure how much different it was in the mid-80's either. I had two girls in my first D&D campaign from '81-'83 out of 7 players.
Dealing with the gamers in the local area, I noticed at least 1:10 were female then. When I went to a predominantly male (focused on engineering, math and comp sci) university in the mid-80's, women were over-represented in the gaming community and still kept about 1:10 ratio (male to female student ratio was closer to 19:1). Individual group ratios were more highly varied, of course.