In The Politics of Autism, I discuss prevalence and talk of an "autism epidemic."
There are a couple of things wrong with this list.
First, if you click through the links, you find that it originates with a 2011 article in The Los Angeles Times. Therefore, the data are at least six years old.
Second, the Times article cites figures from the US Department of Education, which does not collect statistics on clinical diagnoses. Rather, it gathers data from state education agencies, whose definitions of autism vary a great deal. And there often is a mismatch between the written definition of autism and the evaluation procedures. Some states may report higher percentages of students receiving autism services because they have a broader definition or place fewer barriers to families seeking those services.
The Centers for Disease Control has issued estimates of nationwide autism prevalence. These data come from a sample of eleven communities, not any "hard" nationwide count. No such count exists.
There is no national census, registry or list of people who have autism diagnoses.