It used to be banned, but now most high school curriculum's have it as required reading. the book outsiders is no longer banned because just recently i saw and read the book in my high school class.
There are no doubt millions of copies of books within the U.S. that have been banned by someone somewhere.
However, I think your question may have been how many books are currently banned in the...
The very title sounds a little sacrilegious, like Lumen Mundi Venturi- the Latin phrase which means ( the Light of the World To Come) something one DOES not examine with, say a spectroscope ( or...