Source?
Atletico increased his salary 3 times recently so he must be on more than that.
And again why are ppl ignoring that he has already rejected several big clubs? Or do you think those clubs didn't already offer him much more than what he is earning at Atletico?
He rejected them and the club didn't want to get rid either obviously, but him rejecting the offer tells us that either he is happy with the little money he is on currently or that indeed he earns more than ppl think he does. He is very valued there, he has already captained the side a few times when Gabi/Raul Garcia/Godin weren't playing. Their wage bill is the 3rd highest in la liga and they don't have a huge squad which tells me their top player are on good wages (albeit not great).