Help assign Experience on kills?

I'm scripting an RPG game, and I want it so that when players kill NPCs or other Players that they will gain Experience. This is my Experience hierarchy:

Player.Experience.Value

Experience is a Number Value, and the Player value is equivalent to the LocalPlayer. It should be about 10 Exp per 100 damage, and I want it done by damage so that I don't have to assign a separate Exp drop for each NPC.