eBooks continue to exceed the grown of the rest of the market, with combined sales across all segments increasing by 46% ($896 million to $1.3 billion). Much of the growth can be attributed children's ebooks (up 160%), which is still seeing the record breaking 3 digit growth rate that the overall ebook market experienced in 2009 and 2011, but the adult ebook and religious ebook segments are still seeing excellent growth (35.9% and 22.9%, respectively).
According to AAP's publicly available stats, eBooks now account for 22% of the US book market. This change was accomplished in only 5 years.
image by Bill Ward's Brickpile