Does the combat log count overkill per character?

What I mean is, when the game is tracking damage dealt per character, does it count all of the damage the combat log displays that they've done to an enemy, or does it only count the damage that they actually contributed to a kill?  If it's the former, it makes tracking how much damage a class is actually contributing quite a bit harder, because you could do 100+ damage to an enemy that only has a few endurance points left.