I hate to jump in and jump off topic but statements like that really annoy me. First, when a market is tiny but growing even small increases look amazing as a percentage.
And then there's the maturity of the publishing market itself. Anything new that's growing is going to be growing more than the otherwise mature no-growth market.
The question here is: How much new incremental business is this actually creating? Or, much like music CDs years ago, are most people simple trading one format for another newer one?
Yes, those re-sales still count but it also creates a false sense that the market itself is actually growing; that new buyers are coming on board. Again, ask the music industry if they regret getting hooked on the "bonus" revenue from CDs. And how that not only drove people to downloads, but that false growth created a false peak that made the digital crash hurt even more.
Again, please pardon the somewhat off-topic-ness.