Acording to the formula on the armor page for level 70 targets this is a
3.3% to 1.1% incress in damage for armor ranges from 350 to 20,000.
Basicaly 3% on cloth, 2.5% on leather, 2% on mail and 1.5% on plate.
--Barnmaddo
Actually just recently I checked my rogue at lvl 30 and 31 and found that with 3 points in serrated blades it's 8 armor reduction per level (240 at 30 and 248 at 31) however I don't know when this would have been implimented.--Ndoki 20:29, 17 August 2007 (UTC)