Why do you believe that what you wrote is true?
Because I've seen this claim many times over more than a decade, and have seen evidence multiple times. I've also been able to search for it when I was curious and find it without issue.
Here's the first search result, a Vice article from 2018: https://www.vice.com/en/article/evkmz7/study-again-shows-pir...
Why do you believe that what you wrote is true?