The American Association of Publishers has just released the preliminary figures for book, audiobook, and eBook sales in the US market for the month of July 2011 (chart embedded above).

Total reported eBook sales were up slightly from June ($82 million vs $80 million), and the July sales were up 105 percent compared to last July ($40 million vs $82 million). eBook sales also increased year over year, with the year to date showing an increase of 150 percent ($560.5 million vs $221.7 million).

Hardcover sales were also up 30 percent, while paperback and mass market sales were down 25 to 30 percent. Downloaded audiobooks passed CD based audiobooks for the first time as sales of of the latter dropped while sales of the former increased.