The original estimates of the prevalence of autism indicated that it occurred in around 2 per 10,000 people. However, recent estimates place the prevalence as high as or higher than 6 per 1,000 for all autism spectrum disorders combined. The Centers for Disease Control and Prevention (CDC) currently lists the prevalence of autism as 1 in 166 births. It is likely that the increased prevalence of autism is due to increased awareness of the disorder by the population at large as well as by physicians and other providers of service to children and better diagnostic tools that more accurately covers the entire autism spectrum. However, a true increase in the prevalence of autism across time is possible.