As eBooks and eReaders continue to grow in popularity, the sale of print books continues to slow. Although print book sales recently have overtaken e-book sales in the United States, e-book sales in the United States are expected to surpass sales of printed books in the medium-term. In the medium-term, book sales as well as e-book and eBook sales will increase, but the fold will remain strong, as e-book stores continue to evolve into mainstream retailers for books; Nook is an example of this change. A major source of revenue for e-book providers is the sale of Kindles itself; Amazon generated nearly $100 million in revenue on the sale of Kindle hardware in 2011 alone. Amazon's revenue from Kindle hardware is expected to grow by nearly three times to $1.5 billion in 2012. Often print-book publishers also try to leverage the popularity of a popular series of e-books and print books. This is done by producing e-books in the format that can be read by online readers and coming out with the book simultaneously on a printed binding. This can give new readers of the series a chance to discover the series before spending loose change on the first printed book in the series, and if they enjoy the series, encourage them to buy the subsequent print books. Kindle Fire is an example of this, as it includes e-books with the sale of the device.
With the advent of mobile devices, the number of people reading on those devices has increased tremendously. According to the Pew Internet & American Life Project, 45% of American adults read an e-book in 2011, more than double the proportion who read a print book. Over the past five years, e-book sales have increased by a factor of 10 and have outgrown print book sales. Print book sales in the United States are expected to decline as increasing numbers of people read on tablets. According to the American Booksellers Association, e-books made up 8% of all book sales as of mid-2011, up from 2-3% in 2009. In April 2012, it was reported that e-book sales more than doubled in the first three months of 2012 as more people use their iPads and other tablets to read electronic books. 7211a4ac4a