By Steve Windwalker
Originally posted at BookGorilla.com

Following up on our post over at Kindle Nation yesterday about Citigroup analyst Mark Mahaney’s predictions that the Kindle’s slice of total Amazon revenues will continue to rise this year and next, we note (via TechCrunch) that Mahaney has also increased his estimate of how many Kindle devices Amazon will sell this year from 16.5 million to 17.5 million units. In 2012, Mahaney projects another 26 million Kindles to be sold.

These are just projections, but they are pretty dazzling projections. And we think he’s pretty close.

Our sister blog Kindle Nation published a post back on January 13 — Just How Big is the Kindle Revolution? Our Estimates: Amazon Has Sold 12 Million Kindles, and There Were Over 10 Million Paid Kindle eBook Sales in the Last Week of 2010 — where we estimated Amazon’s Kindle unit sales had reached 12 million at that point in mid-January, including about 8 million Kindles sold during calendar year 2010. We went on to project that the “installed base” of Kindles would reach 22 million by the end of 2011 and 35 million by the end of 2012. I don’t recall anyone suggesting that our January numbers were conservative, but Mahaney has left us in the dust: his numbers translate into an “installed base” that that would be about 18% higher than our projection for the end of 2011 and about 50% higher than our projection for the end of 2012.

While the number of Kindles sold is important, the rubber actually hits the road when we look at Mahaney’s projection for the number of Kindle books sold over this period, because that’s where the ebook revolution is being fought, and those are the numbers that will be etched on traditional publishers’ gravestones — apparently much sooner than mainstream projections might have had us believe.

According to Mahaney:

• there were 124 million Kindle books sold in 2010;
• there will be 314 million Kindle books sold in 2011; and
• there will be 752 million Kindle books sold in 2012.

We estimated back in January that Amazon had sold 10 million paid Kindle books during the final week of 2010, and given the fact that the final week of the year will always be far and away the biggest week of the year for ebook sales, this 10-million unit figure seems entirely consistent with Mahaney’s estimates. Taken together, the impact of these numbers is that we would not be surprised to see 25 million paid Kindle books sold the final week of this year, and 50 million next.