Seattle - Amazon Kindle books are now outselling paperbacks, a first for the company.

The online retailer said 115 Kindle paperbacks are selling for every 100 real paperbacks during the quarter. In addition, three times as many Kindle hardcovers are selling compared with their physical counterparts.

The company reported this as part of its quarterly earnings report yesterday.

Amazon did not include the free Kindle books that are available for the e-readers.

Amazon's U.S. Kindle store now contains 810,000 books, 107 of the 112 books on the New York Times best-seller list. About two-thirds of the books cost $9.99 or less, the company said.