Amazon CEO Jeff Bezos was interviewed in the New York Times this past weekend.

Q: Of all the books that Amazon sells, what percentage are digital books?

Bezos: For every 100 copies of a physical book we sell, where we have the Kindle edition, we will sell 48 copies of the Kindle edition. It won’t be too long before we’re selling more electronic books than we are physical books. It’s astonishing.

Amazon has been floating that number since October, when the company also offered that in May the ratio was 35 electronic copies for every 100 physical copies.

The number shocked me when I first heard it, but then we got our first royalty statement for The 100 Best Business Books of All Time. For every 100 copies of the physical book we sold through Amazon, 20 copies of the electronic version were sold. The statement also showed that Amazon is really the only game in the electronic book town.

Let’s make sure to put these numbers in perspective. Amazon only controls about 10% of the overall book market, which means that 3% of the overall book market has gone digital.

The introduction of more devices like Barnes & Noble’s Nook (which is getting warm to lukewarm reviews today) and more vendors like Smashwords will certainly change the marketplace dynamics. Let’s not also forget that Amazon is losing about two dollars on every book is sells right now.

The adoption of digital books is a very real phenomenon. I keep saying we in the middle of a five year disruptive cycle for book publishing. 2010 will be Year Four of the cycle and this is when we will really start seeing measurable effects in the book market as a whole.