Non-Fiction Makes More Money Than Fiction?

Out on a whim I started writing a couple of non-fiction ebooks under a new pen name. As a matter of fact, that was what I used to do as a career before I started writing fiction; before that, I was definitely a fiction and poetry writer (I mean, in my academic years). As of now I seem to be earning more from nonfiction than fiction. It doesn't surprise me though.

A first look at KDP select doesn't look as bad as everyone paints it to be, but then again I am not one to put all my eggs in one basket. Let us say that, out of the three non-fiction ebooks I have published there, only one is enrolled in KDP select. I almost enrolled another one too but backed out soon after (you get three days to quit the program: the 'buyer's remorse' thing). So far so good. We will see how it turns out to be.