If I wrote 20 billion, then that's what Norm told me. If it was 2 billion, I'd like to know, so that I can correct it for a future reprint.

Of course, why would it matter? But I'd like to be accurate in print. Reminds me of the joke about the scientist who tells the guy that the sun might extinguish in 50 billion years. Guy answers back, "Oh, thank goodness. At first, I thought you had said 50 million!" :-)

Don