According to the AAP numbers, that's an increase from 3.94% of the total dollars in January 2010 to 8.68% in 2011 .... I'm curious what that translates to as a percentage of total books sold.
According to Sarah Weinman (news editor for Publishers Marketplace) on twitter, the numbers indicated eBooks were
23.5% of all titles sold in January. I can't get to the article she referenced, as it's behind a $20/month paywall, but she's a very reliable source.
I know there's going to be some "I just got an eReader for Xmas" effect, but 23.5%? Really? I didn't think we'd get THIS far so fast...