Which novel is held by the most libraries in the world?

Question raised last night: which book - specifically, which novel - is held by the most libraries in the world? "Novel" eliminates from the list the first and most obvious that come to mind: The Bible, and the Complete Works of Shakespeare. But novels? Maybe it's our anglo-centrism but I would guess an English-language novels. There must be a few that are held by every library of primarily English-speakers (when you include all of India, that will be a lot people): J. thought Gatsby, but I thought first of Dickens and Twain, either Great Expectations or (more likely) David Copperfield, and either Huck Finn or (more likely) Tom Sawyer. But maybe the 19th century is too far back. Gone With the Wind may be the most popular book of the 20th century, but maybe too American - would rural libraries in China have it? They might be more likely to have The Good Earth (obviously) or Grapes of Wrath. But those may be fading from the canon and from the shelves. Ultimately, I'd have to say it would be one of the books used in thousands, millions of high schools: Catcher in the Rye, Lord of the Flies, or, probably most likely of all, To Kill a Mockingbird. I would guess that's the one in America. What about the world, though? Is there some book translated into a hundred languages that we're missing? Things Fall Apart? (Doubtful) Something in Chinese? French? The French have a slew of their own wildly popular novelists, but none that I think would be likely to be in all U.S. libraries. Anyone ever look this up?