About 82 percent of kids from ages 2 to 17 say they’re video gamers, according to a survey by market researcher NPD Group.

Kids have always been game fans, but the challenge for the games industry remains hanging on to its fans when they become adults. But the average gamer is now 35 years old, according to the Entertainment Software Association.

The survey says about 55.7 million kids are playing games, including 9.7 million who are ages 2 to 5. The largest segment is 9 to 11, with 12.4 million gamers. On average, they play games 10.6 hours a week. The time spent drops down once gamers hit the ages 15 to 17, and females don’t play as much.

“The decline in teen usage of video games is likely due to diversifying, maturing interests, which translates into stiffer competition for their mind and wallet share,” said Anita Frazier analyst at the NPD Group. “In addition to competition from other areas of the entertainment space, more school work, activities, and parent-imposed time limits on gaming are factors which the data suggests may be contributing to this dip in older teen engagement.”

Kids use an average of 2.5 systems to play. Gaming on non-traditional devices such as cell phones and portable media players becomes more popular among older kids. About 51 percent of kid gamers play online, and online players are more likely to be males ages 9 to 14.