Ambitious about Autism is a national charity dedicated to improving opportunities for people with autism. Originally established in 1997 as the TreeHouse Trust, the charity was founded by a group of parents whose children had been diagnosed with autism.
http://www.ambitiousaboutautism.org.uk/page/about_autism/stats_and_facts/index.cfm
This page is really interesting - it provides up to date information relating to statistics around Autism - good information if you are training staff.
http://www.ambitiousaboutautism.org.uk/page/index.cfm