E-book sales of trade titles rose 44% in 2012 and have skyrocketed an astounding 4,660% since the format first began to gain traction in 2008, according to BookStats, the book industry statistical program overseen by the Association of American Publishers and the Book Industry Study Group. The increase in units tracked not too far behind, rising 43% in 2012 to 457 million units sold, and jumping 4,456% since 2008.

As with any new product category, e-books enjoyed their strongest gains, at least in terms of percentage increase, in the first few years following their introduction. In 2008 and 2009, driven by the launch of the Kindle and later the Nook, e-book sales rose 354% and 198%, respectively. As publishers began to make more print books available in digital formats, e-book sales surged from under $900 million in 2010 to over $2 billion the following year, adding $1.24 billion in sales in 2011. The slowdown in growth in 2012 was not unexpected as e-books have become a billion-dollar business, making triple-digit gains a thing of the past. What’s more interesting than the 44% increase in sales in 2012 is that in terms of dollars, e-books also grew at a slower rate in 2012 than in 2011, partly due to lower prices as well as lower unit sales, adding about $933 million in new sales in the most recent year. The increase in 2012 was still good enough to increase the format’s share of the book market to 20% in the year, up from 16% in 2011, according to the BookStats data.

During the 2008–2012 period, trade sales overall rose a total of 14.2%, with the increase due entirely to the introduction of e-books. During the period, sales of print trade books fell 8.4%, from $13.1 billion to just over $12 billion in 2012. The BookStats figures document the important role adult fiction has played in the growth of e-books. In 2012, e-book sales in the segment rose 42%, to $1.8 billion, while sales of adult nonfiction increased 22%. Within the trade category, children’s/young adult had the strongest gain, with sales jumping 117%, from $215.9 million to $469.2 million.

Acceptance of e-books by the public has been a key for the growth of the format, and surveys done by Bowker Market Research show the month by month growth in the percentage of book buyers who have bought at least one e-book in a month. The 25% threshold was first reached in summer 2012; after dipping a bit in the fourth quarter of the year, it bounced back in early 2013 and hit the 26% mark in February.

The 2008–2012 period certainly qualifies as the boom years for e-books, a period during which the format moved from something of a curiosity to a vital part of the publishing industry. And while print sales declined in that same period, what the most recent trends indicate is that digital and print books can coexist. Over the next few years, everyone involved in the book publishing industry will be examining how that print-digital relationship plays out.

E-book Sales Growth, 2008 - 2012 (in millions)

Year 2008 2009 2010 2011 2012
Sales $64.00 $291.0 $869.1 $2,109.0 $3,042.0
% chg -- 354.0% 198.0% 142.0% 44.0%

E-book Unit Growth, 2008 - 2012 (in millions)

Year 2008 2009 2010 2011 2012
Units 10.0 36.1 125.0 320.0 457.0
% chg -- 260.0% 247.00% 156.00% 43.0%