That's because I just made it up.... right now. ;)

You're good.

It would be nice to have hard data

Careful, you're waking the research librarian. She's dangerous when roused. ;) I don't know that this data is publically available for free, but I can certainly make a stab at looking for it.

Ah, the scientific enterprise.

Y'know, I thought about going into science. But ultimately, the idea just didn't appeal. So I do this kind of thing for fun instead. I'm such a freak. :)