In the "age of audio books," artificial intelligence (AI) is taking the lead, with the domestic market for audio books estimated to increase to 4.43 billion yuan (680.5 million US dollars), according to the Beijing Book Fair, which opened Thursday.

Ximalaya FM, a domestic platform for sharing audio content, said its user base, of nearly 450 million activated accounts, had an average listening time of 128 minutes per person.

China's book retail sales totaled 80.3 billion yuan in 2017, up 14.55 percent year on year, according to a report issued at the book fair.

Sales through online channels grew by 25.82 percent year on year, and brick-and-mortar book shops also saw sales increase by 2.33 percent due to China's efforts to encourage people to read, the report said.

"Children's books took a share of 24.64 percent of book sales nationwide, making it the category with the biggest contribution to the total sales growth," it said.

According to Chen Lijun, vice president of China's major online book retailer Dangdang, 410 million children's books were sold in 2017 on the company's website, surging 60 percent year on year.

One-third of the children's books sold on the website were created by domestic authors, according to Chen, who predicts sales will remain high in 2018.

The Beijing Book Fair was first held in 1987 and is hosted by the Publishers Association of China and the Books and Periodicals Distribution Association of China.

This year's book fair attracted 736 exhibitors and will host more than 180 cultural events.