Publishers Weekly reports that in 2011 total book sales fell 2.5 percent and unit sales rose 3.4 percent with the discrepancy due to higher sales of lower-priced e-books.

According to estimates released by BookStats, the annual industry sales survey coordinated by the Association of American Publishers and Book Industry Study Group, book sales in 2011 fell 2.5 percent, to $27.2 billion, and unit sales rose 3.4%, to 2.77 billion, reports Publishers Weekly.

“The increase in the sale of e-books was the major story in 2011. In the trade segment, sales of e-books rose to $2.07 billion from $869 million as units increased 210% to 388 million,” says the story. “With the growth in e-book sales offsetting declines in print, total sales in the trade segment inched ahead, up 0.5%, to $13.97 billion last year. E-books accounted for 15% of all trade sales in 2011, up from 6% in 2010.” Read the complete story here.