In the wake of the UK and US publishers associations announcing declines in e-book sales and revenue, respectively, in 2016, Amazon has announced an increase in revenue in its newly created retail category. Within it are book and e-book revenues, in addition to revenues generated from other media products. Retail revenues increased 15% in Q1 of 2017 over the same period in 2016. While it's impossible to tell how books and e-books contributed to this increase, e-book publishing platform PublishDrive has estimated that Amazon has captured 74% of the e-book market. It's likely that publishers' e-book sales have declined on Amazon in addition to other online and brick-and-mortar retail outlets to reach such a large decline in the overall market.

Source: Forbes April 30, 2017 17:48 UTC