In the UK the number of people with autism is thought to be around 1 in 100 according to the National Autistic Society (NAS). This may be an underestimation because if the condition is not diagnosed when the person is in full-time education, they may never be diagnosed as an adult.
This is a companion discussion topic for the original article at https://patient.info/news-and-features/being-diagnosed-with-autism-as-an-adult