More kids are playing video games between the ages of 2 and 17, according to a new market research report.

The NPD Group reported today that the population of kids ages 2-17 grew just 1.54 percent since 2009. But the population of gamers in that age group has grown 12.68 percent.

This growth means that gaming is now a nearly ubiquitous activity for children in the United States. About 91 percent of kids, or 64 million children, play games, up 9 percentage points from 2009.

The fastest-growing age group is kids ages 2-5, up 17 percentage points compared to 2009. Other fast-growing segments are girls and teens ages 15 to 17. Anita Frazier, analyst at NPD, said that kids account for 44 percent of software sales at retail stores so far this year.

Gaming on mobile devices has experienced the biggest growth in the kids category, up from 8 percent to 38 percent. Gaming on traditional portable handheld gaming devices like the Nintendo DS has grown more modestly, from 38 percent to 45 percent. The change is due to the popularity of tablets, iOS devices and Android smartphones.

But despite the growth in mobile apps gaming, kids and their parents spent more than five times as much on retail games across devices than they did on mobile gaming apps for smartphones and other app-capable devices.

The survey was conducted from Aug. 1 to Aug. 15 this year and was completed by 4,136 kids ages 2 to 17.