What is a normal reading speed for academic literature?

As a student, how I spend my day often involves reading articles on advanced linguistics.
I ask this question because I think I’m a slow reader, but I have no reliable frame of reference to base that impression on.

Today I’ve been reading roughly from 12:00 to 17:00, and made it through 20 pages. By my standards, that’s decent.

How fast can you read complicated material and understand what it says, in pages per hour?

I suppose the question is a bit simplistic; even disregarding that there are no convenient objective measures for complicated-ness, there is variability in margin and font size. Let’s assume average values for both.