Amazon says more people are buying digital books than traditional paper books nowadays.
Amazon says it's selling more electronic books than printed books, less than four years after it started selling e-books.
Since April 1, Amazon says it has sold 105 e-books for every 100 printed books, including printed books for which there is no electronic edition. The comparison excludes free e-books.
Printed books include both hardcover and paperback books. Amazon said in July that e-book sales had outstripped hardcover sales.
Amazon also says the latest and cheapest version of its Kindle e-book reading device is the best-seller of the line, five weeks after it was introduced. It costs $114, and shows ads in standby mode.