Publisher Hachette made approximately 5% of its US revenues from eBooks in 2009

"In the United States, which posted double-digit growth to end September, sales fell by about 20% in the final quarter. During 2008, the Stephenie Meyer saga (Twilight, New Moon, Eclipse and Breaking Dawn) was a huge success, selling over 28 million copies, including 8 million in December alone. Consequently, the drop in Stephenie Meyer sales depressed revenue growth in the final part of 2009, with the impact only partly cushioned by the success of books by Edward Kennedy (True Compass), Uwem Akpan (Say You're One of Them) and Malcolm Gladwell (Outliers and What the Dog Saw). U.S. sales of e-books increased sharply during the year, reaching around 5% of total revenues in December."
Source: Press release from Lagardere, 11th February 2010
Note: "Lagardère Publishing is composed of prestigious brands including Grasset, Larousse and Hatier in France, Anaya in Spain, and Little, Brown and Company and Grand Central Publishing (Hachette Book Group) in the United States." (Source)