According to Amazon.com, the Kindle e-reader has been its #1 bestselling item for the past two years. It is also the most-wished-for, most-gifted, and has the most 5-star reviews of any product on Amazon.com. Amazon.com has announced that Kindle device unit sales accelerated each month during the second quarter, on a sequential month-over-month basis and on a year-over-year basis.

The U.S. Kindle Store now has more than 630,000 books, including New Releases and 106 of the 110 New York Times Best Sellers. Over 510,000 of these books are $9.99 or less, including 75 New York Times Best Sellers. Over 1.8 million free, out-of-copyright, pre-1923 books are also available to read on Kindle.

Over the past three months, for every 100 hardcover books Amazon.com has sold, it has sold 143 Kindle books. Over the past month, for every 100 hardcover books Amazon.com has sold, it has sold 180 Kindle books. This is across Amazon.com's entire U.S. book business and includes sales of hardcover books where there is no Kindle edition. Free Kindle books are excluded. If they were included, this number would be even higher.

Additional statistics include:

• Amazon sold more than 3 times as many Kindle books in the first half of 2010 as in the first half of 2009. 
• The Association of American Publishers' latest data reports that e-book sales grew 163% in the month of May and 207% year-to-date through May. Kindle book sales in May and year-to-date through May exceeded those growth rates. 
• On July 6, Hachette announced that James Patterson had sold 1.14 million e-books to date. Of those, 867,881 were Kindle books. 
• Five authors (Charlaine Harris, Stieg Larsson, Stephenie Meyer, James Patterson, and Nora Roberts) have each sold more than 500,000 Kindle books.