About 1.5 million people in the United States have autism, according to Advancing Futures for Adults with Autism. This number has increased significantly in the past couple of decades, likely due to greater knowledge about the disorder.
Even with that greater knowledge, the number is only an estimate and it becomes murkier when discussing people other than kids.
The number of adults living with autism today is even less certain according to AFFA. “Some sources cite that roughly 80 percent of those individuals with autism are under the age of 22.”