Some interesting statements from their 2007 research:
Heads of Households – Sixty-seven percent of heads of households play computer and video games.
Women – Forty percent of all players are women and women over 18 years of age are one of the industry's fastest growing demographics. Today, adult women represent a greater portion of the game-playing population (33 percent) than boys age 17 or younger (18 percent).
Seniors – Twenty-six percent of game players are over the age of 50, an increase from nine percent in 1999. This figure is sure to rise in coming years with nursing homes and senior centers across the nation now incorporating video games into their activities.
Parents – More than a third (35 percent) of parents play computer and video games and 93 percent of these parents have children who also play them. Sixty-three percent of parents with children under the age of 18 consider computer and video games a positive addition to their children's lives.
Of course, as Luca points out, women 18 and up is a much larger group in general than boys 4-17. This means it should be no surprise that there are more adult women playing video games than there are young boys. It still marks a change though, as the market was, only a few years ago, dominated by young males.