An interesting read. Something that I've always wanted to know is just what the percentage numbers mean. You come close to answering that here.

You say 7.1% of active writers make more than $100.

You also say there are about 30,000 writers. (Which is interesting, I would have thought it was more...)

So, assuming all 30K are 'active' writers, 7% is about 2K writers making > $100... If all 30K are not active that makes the 2K number the upper bound.