Warlock · Affliction · tier 1 · from level 10
Improved Corruption
+42.8 Corruption
5/5 · level 60 · per cast
Improved Corruption
Rank 5/5
Reduces the casting time of your Corruption spell by 2 sec and increases the damage it deals by 10%.
Averages, counting crits and misses, for a level 60 Warlock with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.