BEIJING -- Chinese children read 40 e-books per capita last year, according to a national children digital reading survey reported in Beijing News Thursday.

There were 250 million potential users for children digital reading in 2018, creating a market of 500 billion yuan ($73.7 billion), the survey estimates.

The survey found animals were the most popular protagonists among child readers, and animal themed works took nearly 80 percent of all the e-books finished reading by children. E-books with Chinese content were more attractive to children.

Increasingly Chinese parents were willing to pay for digital reading for children last year, and parents born after 1990 are more receptive to paid digital reading, said the survey, adding that parents from Shanghai and Beijing mostly intended to pay for their children to digitally read.

The survey, conducted by the Chinese Academy of Press and Publication and online reading website KaDa Story, used 5 billion records from 20 million KaDa users over four years.