Wow.
According to research done by AuthorEarnings.com, self-published books account for 31 percent of Kindle electronic book sales, compared with 38 percent for the "big 5" publishing houses, and added that self-published authors earn more in Kindle royalties than Big 5 authors, combined. And self-published authors are now earning nearly 40 percent of all e-book royalties on the Amazon.com Kindle store, according to research by AuthorEarnings.
via Self-published books nearly a third of Amazon Kindle sales - Puget Sound Business Journal.