That was fast. Amazon founder and CEO Jeff Bezos announced that sales of electronic books had surpassed sales of print ones. Since April 1, the online retailer has been selling 105 Kindle e-books for every 100 print books, hardcover and paperback combined. The company said it has sold more than three times as many Kindle books so far in 2011 as it did during the same period last year. "We had high hopes that this would happen eventually, but we never imagined it would happen this quickly," Bezos said. "We've been selling print books for 15 years and Kindle books for less than four years."