E-books Still Outsold by Hardcover and Paperback

As someone pointed out in the comments, these figures ignore self-published ebooks that don't have ISBNs and thus don't show up in Nielsen, BookScan, etc.

Most U.S. self-published ebook authors don't use ISBNs because they're outrageously priced in small quantities, and none of the major ebook outlets (Amazon, B&N, Apple) require them. The situation is somewhat different in other countries, where ISBNs are issued by government agencies for free.

These books are a substantial portion of Amazon's ebook sales, the majority in some genres.

For a more comprehensive take on sales numbers, see:

http://authorearnings.com/