No correlation between atheism and national IQs, claim this random guy. 
You can get anything published in academia.
https://www.jstor.org/stable/24764228?seq=1#page_scan_tab_contents …pic.twitter.com/iCvVqZAoFU
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Hasn't the US in particular recently been seeing considerable increases in agnosticism/atheism and is increasingly unexceptional in that regard for a rich country?
Yep, they started asking in different ways too. These data are about a decade old.