Electronic books provided 23 percent of US publishing revenues in 2012 but sizzling growth rates have eased, according to industry figures released Thursday.

The Association of American Publishers said ebooks gained ground in all categories -- adult fiction and nonfiction, young adult and children's and religious publishing -- and helped the industry increase revenues six percent to $7.1 billion for the year.

The percentage of revenues from ebooks rose to 23 percent of net publisher revenues in 2012, from 17 percent in 2011 and just one percent in 2008, the trade group said.

Growth in ebook sales was 41 percent -- an impressive figure but below the red-hot pace of recent years including 2011, when ebook sales doubled.

For adult fiction and nonfiction, ebooks provided $1.3 billion in revenue, a 33 percent gain.

Sales of children's ebooks were up 120 percent in 2012 to $233 million, driven by huge gains from titles like The Hunger Games.

The association said December data showed slower growth than in the past, suggesting the market is losing momentum.

Adult fiction and non-fiction ebooks showed a gain of 20 percent in December versus the previous year, and sales of children's ebooks fell 21 percent.

"In 2012, ebook revenue growth hit an inflection point -- where it went from reliable triple-digit increases to double-digit increases," the group said in a statement.

"January 2013 could be a month of big increases following a holiday season during which many readers unwrapped new e-readers and tablets."