Amazon said sales of its Kindle e-books have overtaken those of printed books in 2012.
Unaudited figures released by the company show that since the start of the year, for every 100 printed books sold on its site, customers downloaded 114 ebooks, according to the Guardian.
Amazon said the figures included sales of printed books which did not have Kindle editions, but excluded free e-books.
The company said its figures also showed that UK Kindle users were buying four times as many books as they were prior to owning the device.
Amazon revealed that more than 500,000 e-books are priced at 3.99 or less, but said the increase in e-book sales was not just about price as many of its printed books are also sold at a low price.
Three of the 10 most popular Kindle authors of 2012 – Nick Spalding, Katia Lief and Kerry Wilkinson – were published by Amazon's own Kindle Direct Publishing, the company said.
Jorrit Van der Meulen, vice-president of Kindle EU, said: "Customers in the UK are now choosing Kindle books more often than print books, even as our print business continues to grow.
"We hit this milestone in the US less than four years after introducing Kindle, so to reach this landmark after just two years in the UK is remarkable and shows how quickly UK readers are embracing Kindle."
As a result of the success of Kindle, Van der Meulens said Amazon is now selling more books than ever before on behalf of authors and publishers.