One in 68 kids has autism, according to new study that suggests the developmental disorder is on the rise.

The sobering new stat, based on 2010 data released today by the U.S. Centers for Disease Control and Prevention, represents a 29 percent increase in autism prevalence since 2008 and a 62 percent increase since 2006.

One in 42 boys and one in 189 girls fall on the autism spectrum, according to the study.

"The number of children identified with autism continues to increase and the characteristics of these children have changed over time," said study author Coleen Boyle, director of the CDC's National Center on Birth Defects and Developmental Disabilities. "While progress has been made, there is an urgent need to continue the search for answers and provide help now for people living with autism."

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Autism is a spectrum of disorders that affect behavior, communication and social interaction. Symptoms usually appear by age 2, so the CDC studied 8-year-olds at 11 clinics nationwide to come up with the new numbers.

"It really is the best estimate we have for autism in the U.S.," said Boyle.

Advocacy groups say the one in 68 figure is likely an underestimate, but hope it translates into better access to services.

"While the numbers are increasing, the amount of funding remains the same," said Michael Rosen, a spokesman for Autism Speaks. "Autism is a cost to families both emotionally and financially."

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It's unclear from the study whether autism is becoming more common, or simply more recognized and diagnosed. Autism Speaks encourages parents to seek early help for children who fail to meet developmental milestones.

"One way you can make a difference is through early intervention," Rosen said. "But in some communities, the diagnosis is happening later."

White children in the new study were about 30 percent more likely than black children and almost 50 percent more likely than Hispanic children to be diagnosed with autism.

"Awareness is vital," said Rosen. "Especially in minority communities."

While an autism diagnosis can improve access to services for children, Rosen stressed that those services usually expire by age 18.

"We went from one in 110 to one in 88 and now one in 68, and these kids are getting older," he said. "You don't die from autism. You live a long life. So every year 50,000 of these kids reach 18 and lose their services. They need places to live, employment."

"These are people," Rosen added, "not numbers."