Publishers’ sales of audiobooks rose 24.5% in 2018 over 2019, reaching $940 million, according to the recent sales survey sponsored by the Audio Publishers Association. Unlike past surveys, the 2018 report features publishers’ sales receipts, rather than estimated consumer sales.

The report also confirmed the role sales of digital audio have played in the growth in the format. Over 91% of audiobook sales came from the digital format, the APA said.

The survey found that the most popular audiobook genres in the U.S. last year were general fiction, mysteries/thrillers/suspense, and science fiction/fantasy. However, the APA noted, nonfiction audio sales have grown and represented 32.7% of unit sales in 2018, led by general nonfiction, history/biography/memoir, and self-help.

Adults continued to be by far the biggest customers for audiobooks, accounting for just over 91% of revenue last year. While sales of adult and young adult titles each increased by double digits, sales of audiobooks aimed at children grew moderately, the APA said.

The report noted that 44,685 individual audiobook titles were produced last year, up 5.8% from 2017. The association noted, however, that the 2017 title count was revised downward from previous reports.

The sales report is based on figures supplied by 20 audiobook publishers, including all Big 5 houses.