I don't know either, but I'm sure the number is BIG.
But, after conversion, I faithfully carried my little Gideon NT in my breast-pocket during my first tour of duty with the Army.
The great blessing of having Scripture available and being allowed to read it is when in doubt the answer is always there! Isn't this what the Reformation ultimately brought us?
The correct answer is always there.
There are also an indeterminate number of wrong answers there, depending on how non-trivial the question is, how sloppily one exegetes the text, and how knowledgeable one is about the Bible and the culture that produced it.
It's those wrong answers that keep the FR religion forum in business, and the yellow pages under "churches" well-populated.