The Autism and Developmental Disabilities Monitoring (ADDM) Network is a group of programs funded by CDC to determine the number of people with autism spectrum disorders (ASDs) in the United States.

ADDM’s goals are to:

• Provide data about ASD prevalence (how common ASDs are in a specific place and time period).
• Describe the population of children with ASDs.
• Compare ASD prevalence in different groups of children and different areas of the country.
• Identify changes in ASD prevalence over time.
• Understand the impact of autism and related conditions in US communities

http://www.cdc.gov/ncbddd/autism/addm.html

http://www.cdc.gov/ncbddd/autism/states/AL%20Fact%20Sheet%202009.pdf