The latest look at autism in the U.S. shows a startling 30 percent jump among 8-year-olds diagnosed with the disorder in a two-year period, to one in every 68 children.

The Centers for Disease Control and Prevention, which did the survey, says the numbers almost certainly reflect more awareness and diagnosis of kids who would have been missed in years past. The new estimate for 2010 was a jump from one in 88 children in 2008, the last year for which numbers had been available.

“The number of children diagnosed with autism continues to rise,” the agency’s Dr. Coleen Boyle told reporters.

But the CDC noted that the numbers vary greatly from state to state, and it did not use a nationally representative sample, but a look at groups of children in 11 states.