According to a new report from research group NPD, 91 percent (approximately 64 million) of kids ages 2-17 are gaming in the U.S., representing a nine point increase since 2009.

NPD says that while they've seen increases among all age groups, the fastest growth areas are ages 2-5, which has seen a 17 point increase since 2009. Females and teens ages 15-17 are also driving this growth.

“Year-to-date through August 2011, kids comprised 44 percent of new physical software dollar sales, representing a vitally important consumer segment for the games industry,” said Anita Frazier, an analyst for NPD. “Knowing how kids are spending their gaming time and dollars in both traditional and non-traditional outlets is key to staying relevant to this highly engaged audience.”

Unsurprisingly, the platforms seeing the most growth with kids are mobile devices and computers. Since 2009, mobile gaming has jumped from 8 percent to 38 percent while traditional portable gaming devices, such as the Nintendo DS and PSP, increased from 38 to 45 percent.

The data was collected through an online survey in August that included approximately 4,136 individuals ages 2 -17.