Looks like Smashwords updated their Apple iBooks numbers last night. That's just over a month since the last time, which is pretty much what Smashwords advertises as their retailer update schedule.
iBooks does not show a count for free books, though, so I can't see how many copies of The Sixth Discipline I have given away in iBooks. It's over 1,000 now in the Kindle store, and a few hundred on the Nook, but the Barnes & Noble numbers are out of date by a month or so. Smashwords lists free downloads in with the sample downloads, so it's hard to get a total count, but the book is free there, too!