You got to be careful here. Countries that don’t vaccinate also don’t care to diagnose autism. For example, according to this site(https://www.marketwatch.com/story/this-is-the-most-anti-vaxx...) the most antivax country in the world is Ukraine and they definitely not up to par with US on diagnosing autism according to their autism awareness project: https://child.ua/en/projects/autism-awareness-ukraine/