E-books became the publishing industry’s single bestselling format for adult fiction in 2011, with sales of $1.27 billion, according to the results of a survey released Wednesday by the Book Industry Study Group (BISG); however, combined print formats (hardcover, trade paper, and mass market) still represented the majority of publishers’ revenue in the category, at $2.84 billion.

In the overall trade sector, publishers’ net revenue from sales of e-books reached $2.07 billion, more than double the $869 million in e-book sales in 2010. Publishers’ combined trade print formats (hardcover, trade paper, and mass market) still represented the majority of publisher’s net revenue at $11.1 billion in 2011.

The survey, co-produced by BISG and the Association of American Publishers, also revealed that, though revenue in the overall trade sector was relatively flat ($13.97 billion in 2011, just a 0.5 percent increase over 2010’s $13.90 billion), children’s books, including YA, grew 12 percent in 2011, to $2.78 billion from $2.48 billion in 2010.

Despite the closing of Borders last year, the study found that brick-and-mortar stores remained the number-one sales channel for books: Net revenue was $8.59 billion, representing 31.5 percent of publishers’ total net dollar sales (a decline of 12.6 percent from 2010).

Publisher revenue from online sales increased by 35 percent, from $3.72 billion in 2010 to $5.04 billion in 2011.

“I would never dare to call an industry healthy, but it certainly seems to be robust,” said Dominique Raccah, the publisher of Sourcebooks and co-chairwoman of the Book Industry Study Group, as reported by the New York Times. “We, as an industry, appear to be getting books into more hands.”