On the back of sluggish manga sales and growing demand for online publications, magazine sales by value in 2016 are expected to fall short of that of books in Japan for the first time in 41 years, a research institute said Monday.

The reversal of the long-held trend of magazines selling more than books is a major concern for small bookshops, many of which consider magazines their mainstay products.

Sales of magazines, excluding e-publications, are expected to slip 7.7 percent from a year earlier to around ¥720 billion in 2016, down for the 19th consecutive year, with the market value falling to about 46 percent of its peak in 1997, according to an estimate by the Research Institute for Publications.

Book sales are estimated to have dropped 1.6 percent from the previous year to around ¥730 billion, marking the 10th straight yearly fall. But the drop was limited thanks to robust sales of the latest book in the Harry Potter series and "Tensai" ("Genius") by former Tokyo Gov. Shintaro Ishihara, the institute said.

While weekly magazine Shukan Bunshun, which ran a series of exclusive stories, and women's fashion and beauty magazines saw solid sales, other magazines targeting men or focusing on hobbies are continuing to suffer through sluggish times.

An official at the institute attributed the weak magazine performance to a notable decline in comic book sales.

"With the spread of electronic publications, more consumers are now thinking they do not have to read manga in paper magazines," the official said.

The institute estimates that combined sales of books and magazines will sag about 4.7 percent from the year before to ¥1.45 trillion, falling for the 12th straight year and coming below the ¥1.5 trillion mark for the first time in 35 years.