While I admit this is a male dominated profession, in my experience it's more like an 80/20 split. At the very least 90/10. I think JHardy is correct that a disproportionate amount of women filled out the survey. They are probably concentrating on important stuff like work, unlike myself.
on a serious note.... the rate at which women drop out of technical fields in college is quite high. They see the male dominated atmosphere, and many choose to go into a more humanitarian major. Since they don't graduate as engineers, there aren't as many in the industry. kinda sad.... it's an endless cycle. women drop out because it is male-dominated so the stats won't change very easily. unless the stereotypes change on what engineering life entails, i don't think the percentages will go up.