A new report from the Centers for Disease Control and Prevention (CDC) shows a 78% rise in the prevalence of autism spectrum disorders (ASDs) in United States since 2002 and a 23% increase since the last report in 2009.

According to the CDC, some of this increase can be attributed to the way children with ASD are identified, diagnosed, and served in their communities, although exactly how much is due to these factors is unknown.

"These data confirm that the estimated prevalence of ASDS identified in the ADDM network surveillance populations continues to increase. The extent to which these increases reflect better case ascertainment as a result of increases in awareness and access to services or true increases in prevalence of ASD symptoms is not known," the report authors write.

"Unfortunately, 40% of the children in this study aren't getting a diagnosis until after age 4. We are working hard to change that," said Dr. Boyle.

Investigators reported a wide variation in overall ASD prevalence across the 14 surveillance sites; prevalence ranged from 1 in 210 children in Alabama to 1 in 47 children in Utah.

Additionally, there was wide variation in prevalence estimates by sex and race and ethnic group. Boys were 5 times more likely than girls to have an ASD diagnosis. The largest increases were among Hispanic and black children.

Despite the wide variance in collected data, one thing is certain — there are many children and families who need help and it is therefore very important to continue to track autism spectrum disorders in order to help improve services that are available to autistic children.