According to the Wizards Optimisation forums for 4e:
"What I've observed is: 14 DPR(1st), 20 DPR(6th), 40 DPR(12th), 60 DPR(16th), 100 DPR (24th), 150 DPR(30th)"
DPR meaning damage per round.
If you're going to go "that's not possible", one of many character builds that accomplish it is here...