More than half, Christian. Or in other words, I'm doing a years-long process of reading the entire thing. I've finished the New Testament, and am partway through the Old Testament (and I intend to read ALL of it, including all of the books that some branches but not all use, plus stuff like the Book of Enoch, etc.). Not that I'll stop there...there's still the holy books of other faiths (Torah, Koran, Bhagavad Gita (sp?), and the other stuff Frodo listed), plus the best additional Christian works (Origen and Augustine, Aquinas, etc.), plus additional works from other faiths, etc, etc, etc. This will take some time.
Hughento, congratulations! Leviticus is one zillion rules with a little action in the center - 'And Aaron's sons offered unholy fire to THE LORD, and THE LORD fried their asses', or something like that.
Vorlon, I am impressed.