The earliest reports from the ADDM Network provided
estimates of ASD prevalence among children aged 8 years from
six sites for the 2000 surveillance year (8) and from 14 sites
for the 2002 surveillance year (9). Combined data from all
sites in each respective surveillance year indicate that ASD
prevalence estimates were similar for both years: 6.7 per 1,000
in 2000 (range among six sites: 4.5–9.9) and 6.6 per 1,000
in 2002 (range among 14 sites: 3.3–10.6), or approximately
one in every 150 children aged 8 years. A subsequent ADDM