I only know that I read that many because I owned that many books (and didn't own every book I ever read). I was 26 then, and reading since 5-6, so that's really only 10 books a year. The real number of books at that point might have been more like 3000 - but I did re-read a lot of the books I owned so maybe not.
Since this time last year, I've probably read 30+ books. Gotta love the Kindle and Kindle Unlimited.