If you want some stats, I just did a quick and dirty check of a torrent site to see how prevalent e-book piracy is. I chose first the ebook section, then the movies section to compare. In both secions I chose the "mystery" sub-section and then rated by highest number of completed downloads.
Mystery (ebook) - Dan Brown Book Collection - 29275 downloads
Mystery (movie) - The Davinci Code - 1979394 downloads
EDIT: I think I'm actually more worried by the taste of the downloaders than the stats
