“Audiobooks are the golden child of publishing at the moment,” said Orna O’Brien, conference manager of Quantum, the digital conference that preceded the opening of the London Book Fair on Monday. The afternoon of Quantum was dedicated to discussing growth in the audiobooks sector.

Michele Cobb, executive director of the Audio Publishers Association in the United States, presented the results of the organization’s annual sales survey. “The APA estimates that audiobook sales in 2016 totaled more than $2.1 billion, up 18.2% over 2015, and with a corresponding 33.9% increase in units," Cobb reported. "This is the third consecutive year that audiobook sales have expanded by nearly 20%.”

The growth is commensurate with the growth of the audience for audiobooks. Cobb said that "24% of Americans, or more than 67 million people, have finished listening to at least one audiobook in the last year.” That is a 22% increase over 2015.

With more than 50,000 new audiobook titles published in the United States in 2016, listeners have more selection than ever; the most popular genres for new books were mysteries/thrillers/suspense, followed by science fiction/fantasy, and romance.

Smartphones are the most popular way for people to listen to audiobooks, having been cited by more than 29% of users as their main means of listening to books. The majority of people are listening at home (57%) followed by in their cars or other means of commuting and transportation (32%); more than half of listeners are not multi-tasking while listening to audiobooks.

The survey also indicated that dedicated fans of audiobooks tend to be podcast listeners; respondents who identified as podcast listeners said they listened to twice as many audiobooks in the past 12 months as nonpodcast consumers.

The expectation of future growth in the audio market is tied to demographics, with audiobook listeners skewing young. According to the APA, 48% of audiobook listeners in the U.S. are under the age of 35.

“Audio is not a blip,” David Shelley, CEO of Hachette UK, said early in the day. “Audiobooks could be one of the biggest parts of our business. It has doubled in the last two years. It is a completely different way of transmitting our books to people. I would put some money on it that audio is going to continue being a central piece of our business going forward."