I believe a lot of the difference is indeed in diagnosis. People not familiar with autism intimately tend to think of only the most severe cases. But a large % of autistic kids are completely mainstreamed and you would not know. You might just think them shy or odd.
20, even 10 years ago most of the milder cases and many of the moderate to severe would NOT have been diagnosed and I suspect they still would not be in the Amish community. At times, I wonder if my own husband in todays world would have been diagnosed mild Aspergers.
And yes, I grew up in Lancaster, they eat plenty of crap.
MTA: because it is rare I dont have more to say
"When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - my daughter Age 7