The Victory Lap Tour...and a Math Problem That's Really Going to be a Problem

Today, J.K. Rowling updated her website to announce that a few months after the release of Deathly Hallows she will be touring the United States.  The tour (officially titled "The Open Book Tour", although I think my title is better) will include 4 stops--three for kids only (but who cares about those?) and one in New York that will be open to fans of all ages!

As the info on Jo's website says, the sweepstakes to win tickets to the all ages event will begin July 30, on Scholastic's website.  There will be 1,000 winners.

Of course, I will be entering regardless, but just to keep my expectations realistic I thought it would be a good idea to calculate my chances of winning.  Now there isn't any real way knowing exactly how many Harry Potter fans there are, but Half-Blood Prince sold 6.9 million copies in the United States and that seems to be just about as good a number to use as any.  (Of course, hopefully some of those fans aren't die hard enough to travel all the way to New York, but I digress....)  So, 6.9 million people vying for 1000 tickets....*pulling out calculator*.....means that basically 1 out of every 7,000 of us will get a ticket.  I think?