Amazon.com now sells more Kindle books than print books, the company announced today.

Since April 1, Amazon has sold 105 Kindle books for every 100 print books. The company does not release total sales figures for Kindle books or e-readers.

The Kindle was introduced in 2007, and the e-book format has grown in popularity ever since. In July 2010, Amazon said Kindle book sales had surpassed hardcover book sales. E-book sales then surpassed paperback sales in January.

We had high hopes that this would happen eventually, but we never imagined it would happen this quickly. We've been selling print books for 15 years and Kindle books for less than four years, Amazon.com CEO Jeff Bezos said in a statement. Bezos founded the company in 1995.

Bezos also said the ad-subsidized Kindle with Special Offers, which was released in April for $114, has become the most popular version of the e-book reader.

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