Technology and computer book publisher O'Reilly has revealed that 88 per cent of its unit sales in 2010 were ebooks, with print editions and paid-for video taking up the other 12 per cent combined. In addition, 79 per cent of its dollar revenue was generated by digital versions of its titles.

However, statistics also show that the rapid rise in popularity of ebooks and digital editions is faster than the decline in sales of print titles, thereby suggesting that both can co-exist.

As part of a piece posted on, Mike Hendrickson, the publisher's vice president for content strategy explains: "The big, and more likely HUGE, news is that ebooks represent about 88 per cent of our unit sales, and 79 per cent of our dollar sales on What is really impressive is that the growth of our digital products is moving faster than the decline of our print products. This suggests to me that we are not seeing one product type cannibalizing another - rather they are supplementing each other."

The report also shows that the popularity of the PDF format is diminishing and that EPUB and MOBI files (the latter being the primary format for the Amazon Kindle) are zooming up the charts: "Print is slowly declining, and EPUB, Mobi, and Ebooks are skyrocketing off the chart at a rate faster than print is declining," says Hendrickson.

"PDF is declining and when you think about it, this makes sense. O'Reilly used to offer two type of book product: print and a PDF. Now we offer our content in virtually any form a reader would like it. So with Mobi, EPUB, and Ebooks, we are seeing the less useful PDF decline significantly."

Naturally, as a technology book publisher, it seems natural that O'Reilly's customers would favour digital editions in preference to print. It will be interesting to see how these statistics stack up against fiction book publishers and the like.