CFO Tom Szkutak said that while sales of the Kindle have exceeded expectations, it does not plan to release a new version of the e-reader until 2009 "at the earliest." He noted that Amazon has ramped up manufacturing capacity for Kindle, and the device is in stock. When the Kindle was introduced last November, the readers quickly went out of stock. Amazon said the e-book reader now accounts for more than 10% of unit sales for books that are available both in digital and print formats. Bezos said purchase of e-books is "additive" to sales of print books with Kindle e-book buyers tending to buy as many print books in addition to e-books.