In what it describes as "a tough year for publishing overall," the BISG's Book Industry Trends 2009 survey-to be published in full in July-found that the "religious segment underperformed the book publishing industry as a whole in 2008, with revenues declining 10% against total industry growth of 1%."

In a statement announcing the forthcoming release, the BISG added that while the economic downturn "played a role" in the recent performance of religious books, "sales in this sales had already been plateauing over the last few years."

According to the BISG research, net revenues of U.S. publishers reached $40 billion last year, up 1% over 2007. Unit sales totaled 3 billion, down 1.5% over the previous year. Trade publishers said three issues had dominated their thinking, BISG reported: the challenging economy, digital publishing trends and the need for changes in industry practices.

"Although trade publishing is not a sector typically known for swift, sweeping change," the BISG said, its Trends report had found "that many insiders think the severity of the current recession combined with the advances in digital publishing will make significant changes in business models and processes happen faster than the industry has ever seen before."

Two growth areas in 2008 were professional books (up 4%) and elementary-high school and college books (each up 4.5%).

Book Industry Trends 2009 will be available for $125 a copy to BISG member, $875 to non-members. To pre-order, go to http://www.bisg.org/publications/trends2009.html.