At this point it's not a matter of industry not hiring. And it's not a matter of girls not being in the gaming space, though the core gamers are still primarily men. It is true that the core gaming scene is still less than inviting to women, being full of sexist behavior. Still, I would expect to see higher numbers than this. Part of it may be that women are not willing to put themselves through the same terrible working conditions that men are putting up with in crunch - that men seem to have more raw passion for games than women. This is probably an extension of the core gamer demographic, again.
It would be interesting to see a comparison of the statistics for women in computer science, and women in each subgenre of gaming - for example, are there more women in mobile/facebook games? Are women in the gaming industry primarily artists, designers, or programmers? Unfortunately the original survey data at www.creativeskillset.org is rather thick to get through - it would be great to see this presented as an info-graphic or chart.
Being a woman coming into this industry, I'm a little concerned at the backward movement. While I'm not worried about blatant sexism, being treated as an outsider in teams is something I have heard about, and something that the industry gals over at GeekGirlCon have mentioned in the past. It's unfortunate that women in gaming communities and in the industry must prove themselves to be "real" in the eyes of their male colleagues - heaven forbid she might be a "fake" gamer-girl. That said, I personally haven't experienced any awkwardness in working with my classmates so far - I guess I come off as a fairly authentic gamer! Being assertive and honest seems to be a great policy in getting around as a female game programmer so far.