Many seemed to have made that assumption of fact, but I've not seen a shred of data to back it up. That said, it's almost impossible to prove or deny based upon any data that would be available anyway, but that surely hasn't stopped some from jumping to conclusions on a purely correlative or anecdotal basis (or worse, on theoretical grounds rooted in some irrelevant historical context).
Many seemed to have made that assumption of fact, but I've not seen a shred of data to back it up. That said, it's almost impossible to prove or deny based upon any data that would be available anyway, but that surely hasn't stopped some from jumping to conclusions on a purely correlative or anecdotal basis (or worse, on theoretical grounds rooted in some irrelevant historical context).