Sales of online manga comics in 2017 surpassed those of printed books for the first time, a Japanese industry research institute said Monday, highlighting a shift in readers' preferences.

According to a survey by the Research Institute for Publications, sales of digital manga last year are estimated to have risen 17.2 percent from a year earlier to 171.1 billion yen ($1.6 billion), while sales of book editions fell roughly 14.4 percent to 166.6 billion yen.

The research body of the All Japan Magazine and Book Publisher's and Editor's Association said consumers are increasingly drawn to viewing online content partly due to discount campaigns for popular e-works in the past.

The conclusion of some popular manga series and a lack of new blockbuster hits are also believed to be behind the decline in sales of book editions, said the Tokyo-based research body.

Combined sales of books and online manga were almost unchanged in 2017, down 0.9 percent from a year earlier.