Just guess then. His ERA was under 3 in 2008, 4.8 in 2011, 2.2 or so this year although going up in AL... and then mid 3's in 2009/2010...
The average ERA there is probably 3.5 or so. Nothing wrong with a 3.5 ERA. And hell, if you take out 2011, the outlier, it is more like 3. So to say hes been as garbage as a piece of shit like Correia is just stupid. I guess if you want to dumb the argument down and compare Dempster's career stats when he hasn't been the same guy lately due to major arm injuries/surgery/closer converting, then go ahead.