jpch - 12:36 pm on Mar 29, 2013 (gmt 0)
It depends...like most everything else with AdSense there is no hard and fast rule. I have two pages that are very specific/niche and they consistently average about 8% CTR with a very high RPM. I'd be retired by now if all my pages did as well as these two but since they only get about 200 page views/day between the two of them that's going to take a while.
Meanwhile, the bulk of my pages consistently average less than 3% CTR and a much lower RPM. So, if there's any rule that seems to be consistent from my experience it's what HuskyPup has experienced...the more PV's the lower the CTR.