Enemy Stun threshold?

Anyone know the average enemy stun threshold?

Like how much damage does a person have to do all at once to stun a normal white mob?

I know physical damage and melee damage get their own 50% More Multipliers but like I am having a hard time getting a read on this.

I do see that after stunning an enemy once it takes about 5 to 10 times as much to stun them again.

Edit: I am noticing life doesn't seem to matter as much. I am stunning Rares with the same ammount of stun damage as the whites.