Despite a less-than-ideal environment—no breakout bestsellers on the adult fiction side and a lengthy, brutal election cycle that sucked nearly all of the air out of the cultural conversation—unit sales of print books were up 3.3% in 2016 over 2015. Total print unit sales hit 674 million, marking the third-straight year of growth, according to Nielsen BookScan, which tracks about 80% of print sales in the U.S.

Most print formats had an outstanding year, with hardcover up 5.4%, trade paperback up 4%, and board books up 7.4%. Mass market has been on the wane since the introduction of e-books, and its slide continued in 2016 with a 7.7% drop in unit sales. Physical audio, where sales were down 13.5% on the year, also took a big hit from digital.

The largest gains came in the adult nonfiction category, where sales were up 6.9% from 2015. Several subcategories posted substantial increases, among them crafts and hobbies, where the adult coloring book boom—though slowing down from 2015’s blitz—continues to have a large impact. The religion and self-help areas also saw boosts, though for different reasons. Several big-name religion authors published new titles last year and racked up six-figure sales (Pope Francis, Lysa Terkeurst, Sarah Young), whereas backlist powered the self-help category: of the top five self-help titles, only one, Angela Duckworth’s Grit, was published in 2016.

Adult fiction had an off year, with sales down 1%. Missing from 2016 was a new bestseller of the caliber of The Girl on the Train or Go Set a Watchman. Indeed, the paperback edition of The Girl on the Train was the bestselling adult fiction title of the year, at 955,000 units—almost a quarter million copies ahead of the #2 fiction title, Fredrik Backman’s 2015 hit, A Man Called Ove. Nearly all fiction subcategories closed out the year lower than in 2015. The lone bright spot in fiction was comics and graphic novels, which had a 12% increase on the year.

Juvenile fiction was up 3.8 percent from 2015, and was led by the year’s far-and-away bestselling title overall, J.K. Rowling’s Harry Potter and the Cursed Child: Parts 1 and 2, which sold 4.5 million print copies. It was one of only three titles to sell more than a million units; its company in the million-plus club were Jeff Kinney’s latest Wimpy Kid book, Double Down (1.1 million units) and Bill O’Reilly and Martin Dugard’s Killing the Rising Sun (1.1 million units). In 2015, six titles sold more than a million print copies.

The mass merchandiser channel, which includes large chains such as Walmart and Costco, saw sales drop for the third year in a row, down 5.3%. Its losses were more than made up for in the retail and club channel, where sales climbed 5%. That channel is composed of independent and chain bookstores, as well as Amazon.

Unit Sales of Print Books (in thousands), 2013–2016

2013 2014 2015 2016 Change 2015–2016 Total 620,044 635,093 652,673 674,151 3.29% By Channel Retail & Club 501,658 518,901 546,719 573,761 4.95% Mass Merch./Other 118,385 116,191 105,953 100,389 -5.25% By Category Adult Nonfiction 236,833 240,130 256,042 273,589 6.85% Adult Fiction 150,590 138,712 141,690 140,221 -1.04% Juvenile Nonfiction 42,283 48,882 54,624 55,456 1.52% Juvenile Fiction 157,707 176,685 171,383 178,043 3.8% By Format Hardcover 168,250 173,483 178,255 187,940 5.43% Trade Paper 324,701 338,940 355,737 370,019 4.01% Mass Market 80,020 71,758 64,318 59,357 -7.71% Board Books 23,069 27,092 30,978 33,280 7.43% Audio 5,116 5,128 4,434 3,836 -13.49%

Source: Nielsen Bookscan

Correction: A previous version of this article listed an incorrect figure for total unit sales of children's fiction in 2016.