You are giving J.K. Rowling too much credit by combing 7 books into 1.
Doubt one of those books would be in the top 10.
Especially if you take into account that there are other languages the bible was printed in over the centuries than just English.The Gideons, although I never actually have taken note of which version they place. But King James, New International, New American, etc, etc. I have little doubt that an "all versions" total of the Bible would be runaway #1 on this list.