Trace a claim to its source

I keep seeing this claim: {{claim}}

Tell me what would count as a primary source for it, what the claim would have to
measure to be meaningful, and the ways a number like this usually gets distorted as
it is repeated.

If you do not know the original source, say so rather than naming a plausible one.
Then tell me how I would go and find it.

What to fill in

{{claim}}

The claim — e.g. people copy and paste 60 times a day