And yet, I believe female readership in the 1940s was nearly half, I'll have to dig around and find that book which has the stats. I think it was Les Daniels book on Wonder Woman.
I believe manga has a higher female readership than regular comic books.
IIRC CrossGen had a higher than average female readership than the usual American comic books of the time.
I'd say webcomics also have a large number of female readers (and creators).
I wonder how many stats there are on this through the years?