So I would feel safe pointing to that report and saying
unit sales of indie
books on the bestseller lists on Amazon are on the same order of magnitude as
trade published books on the bestseller lists on Amazon.
In the same year ebooks accounted for nearly a quarter of
trade publishing revenues, and by 2013 more than half of
unit sales, according to a July 2014
Book Industry Study Group report by Ted Hill and Kate Lara titled Digital
Books and the New Subscription Economy.