The American Association of Publishers has released its estimated sales figures for August 2011, and the one bright spot was eBook and audiobook sales.

Sales are down across the board, with adult hardcover, children’s books, and adult paperbacks all showing a double digit decrease. The worst by far was the adult paperbacks, and that is probably not due to eBooks cannibalizing the sales.

eBook sales were up 116% in August, but that is only compared to last year’s figures. eBook sales are actually up only a small amount over July 2011 ($88m vs $82m). Sales of paper books dropped far more than eBooks gained.

On a related note, audiobook sales were also up, with August 2011 returning $16.7m (vs $15m in July 2010).