A recent media release (see http://www.cdc.gov/media/releases/2014/p0327-autism-spectrum-disorder.h… ) says
The Centers for Disease Control and Prevention (CDC) estimates that 1 in 68 children (or 14.7 per 1,000 eight-year-olds) in multiple communities in the United States has been identified with autism spectrum disorder (ASD). This new estimate is roughly 30 percent higher than previous estimates reported in 2012 of 1 in 88 children (11.3 per 1,000 eight year olds) being identified with an autism spectrum disorder. The number of children identified with ASD ranged from 1 in 175 children in Alabama to 1 in 45 children in New Jersey.
Note that recent (2012) Australian data on the prevalence of ASD shows 1 in 62 children in this country have a diagnosis ... see http://a4.org.au/a4/node/695 and http://a4.org.au/a4/node/622 There is nothing to celebrate in rising autism rates because people who are properly diagnosed with autism have significant disability that "requires support".