Correlation between pre-flop raises and stakes?

I am curious as to whether or not the frequency of pre-flop raises increases as stakes increase. Is there a clear answer to this or is it still just "it depends"?

They must.. half the 10NL crowd raises 1BB with AA. (the other half throws an all-in)

Depends on the table, I think.

Overall I'd say you get less limpers at higher stakes. But they're generally just playing tighter, not raising a larger percentage. Most guys are raising pocket pairs and AQ+. Lots of guys limping small pockets...

I think the higher you get, the more value people place on a raise when they enter the pot. But to repeat, I think they enter the pot less with limping hands, and just play the raising hands (or raise the limping hands, maybe).

Regardless, this is an "it depends" answer, as are most poker answers.