Does "takes percent less damage from xxx" stack, and, if so, how?

[bryanw1995]

I’m using the following:

Mark of Divinity: takes 8% less dmg from aetherials
Aether Soul: takes 6% less dmg from aetherials

Does this add up to taking 14% less damage from aetherials, does it just take the highest value, or is it multiplicative?