What has been a worrying trend for ebook publishers in the U.S. continued through September 2013, according to the latest report from the Association of American Publishers.

Ebook sales in the month were up 3.5% versus the same period last year, a marked slowdown from the double- and triple-digit growth rates for ebooks in years past. Year-to-date, ebook sales for publishers are up 2.2% to $983.6 million.

By contrast, adult ebook sales were up 30.7% in Sept. 2012 versus the same month a year prior. Year-to-date in 2012, ebooks were up 36.2%.

Sales of children’s ebooks continue to sag versus last year when the Hunger Games titles regularly hit best-seller lists. Sales of children’s ebooks are down 5.7% in the month of September and 37.8% for the year to $122.4 million.

Religious ebooks are up slightly to $47.4 million in sales versus a year ago, an increase of 2.6%.

Across all three categories that the AAP tracks on a monthly basis, ebooks accounted for $1.15 billion in revenue, down about 4% from the same time last year.

That publisher ebook sales have basically been flat in 2013 has been a widely discussed trend in publishing circles. What is often left out of the discussion — though is being included more — is that the AAP report doesn’t include self-published titles and therefore doesn’t represent the entirety of ebook sales growth in the U.S.