What Is A Typical Benchmark For # Of Rage Rounds By12th?

[K-kun the Insane]

Exactly what it says on the tin. I'm not looking for a maximum nor an optimum, just a comfortable ammount.
26?
37?
43?

[blashimov]

26 you get just from 12 levels of barbarian
add con to that, so about 30.

[Chess Pwn]

I've done pfs with 12-16 rounds and have been fine on rounds.