Mine is about 80 percent non fiction, 20 percent fiction. It is only in recent years that I have started to read fiction again, after 5 years writing my own non fiction book. My library contains lots of different types of books - popular science, religion, mythology, alternative history, mind, body and spirit, travel books, cook books, reference books - dictionaries, thesaurus etc (essential for any writer) and of course books about writing.
I used to me like MMMM and read purely for knowledge - this is fine, but I got to the point where I had forgotten what it was to read simply for pleasure. I missed that, so it has been a joy to rediscover good novels.