Unit sales of print books sold through outlets measured by Nielsen BookScan fell 10.2%, to 307.1 million, in the first six months of 2011 ended July 3. The decline comes as no surprise as e-book sales continued to eat into sales of physical books, and the weak economy limited consumer purchases of discretionary items. While it is difficult to separate the impact of the economy compared to the shift to e-books on the sale of print books, the two areas where the downturn was the greatest suggests that e-books are having the more dramatic impact on print sales.

Adult fiction has been the most affected by e-book sales. Bowker's recently released 2010–2011 U.S. Book Consumer Demographics & Buying Behaviors Annual Review showed that e-book sales accounted for 12% of adult fiction in the fourth quarter of 2010, the highest percentage of all segments. While sales of adult fiction e-books has grown, the BookScan figures show the sales of adult fiction print units fell by 25.7% in the six-month period, by far the steepest decline among the major book segments. The sales decline of adult nonfiction, where Bowker reported that e-books accounted for 5% of sales, was much more modest in the period, down only 2.7%. In the juvenile segments, there was less spread between fiction and nonfiction, with fiction sales off 7.4% and nonfiction down 6.7%. (Bowker reported that e-books represented 4% of all juvenile sales.)

Monthly data released by the Association of American Publishers has shown steep drops in sales of mass market paperbacks through the first four months of 2011, and the BookScan figures reinforce how dramatic the decline in that format has been. Through the first half of the year, unit sales of mass market paperbacks fell 26.6%. A number of mass market paperbacks' most popular genres—romance, mystery, and science fiction/fantasy—are moving rapidly to digital, and that, combined with loss of shelf space, continues to put pressure on sales of the format.

Hardcover unit sales, once thought to be the most vulnerable format to e-book inroads, dropped 9.5% in the first six months, while trade paperback sales declined 6.8%. The spoken-word audio market is facing its own transition as more sales move to digital downloads; in the first half of 2011, sales of physical audiobooks declined 11.1%.

Unit Sales, Six-Month Performance, 2010–2011

Category July 3, 2011 July 4, 2010 % Change
Adult Nonfiction 128,524,000 132,173,000 -2.7%
Adult Fiction 79,879,000 100,413,000 -25.7
Juvenile Nonfiction 16,220,000 17,384,000 -6.7
Juvenile Fiction 64,690,000 69,858,000 -7.4

Format July 3, 2011 July 4, 2010 % Change
Audio 2,582,000 2,905,000 -11.1%
Hardcover 72,019,000 79,547,000 -9.5
Mass Market Paperback 42,874,000 58,438,000 -26.6
Trade Paperback 173,185,000 185,785,000 -6.8
Total* 307,143,000 341,962,000 -10.2