Unit sales of print books were up 5% in the week ended July 26, 2015, compared to the similar week last year, at outlets that report to Nielsen BookScan. The strong gains followed an impressive 13% increase the prior week, due to the release of Harper Lee’s Go Set a Watchman, which set print sales records its debut week and has sold 983,000 copies to date. The Watchman effect is also behind the double-digit gains for the hardcover format and the adult fiction category this week. Adult nonfiction saw an 11% increase in unit sales, fueled by the release of YouTube star Miranda Sings’s comedic, “unhelpful” self-help book, Selp-Helf, and by continuing demand for Marie Kondo’s The Life-Changing Magic of Tidying Up and Ta-Nehisi Coates’s Between the World and Me. E.L. James’s Grey—which, in its six weeks on sale, has sold just over one million copies—is a big part of the growth in the trade paperback format, along with John Green’s Paper Towns and Andy Weir’s The Martian, both of which have forthcoming film adaptations.

Unit Sales of Print Books by Channel

July 27, 2014 July 26, 2015 % Chge Week % Chge YTD
Total 10,901 11,457 5% 1%
Mass Merch./Other 1,851 1,751 -5 -9
Retail & Club 9,050 9,705 7 4

Unit Sales of Print Books by Category

July 27, 2014 July 26, 2015 % Chge Week % Chge YTD
Adult Nonfiction 3,975 4,202 6% 4%
Adult Fiction 2,810 3,128 11 3
Juvenile Nonfiction 791 944 19 10
Juvenile Fiction 2,898 2,766 -4 -5

Unit Sales of Print Books by Format

July 27, 2014 July 26, 2015 % Chge Week % Chge YTD
Hardcover 2,422 2,712 12% 3%
Trade Paperback 6,386 6,716 5 2
Mass Market Paperback 1,383 1,281 -7 -10
Board Books 394 450 14 10
Audio 93 89 -4 -16

Source: Nielsen BookScan and Publishers Weekly. Nielsen BookScan’s U.S. Consumer Market Panel covers approximately 80% of the print book market and continues to grow.