FRANKFURT - Even before the world’s biggest book fair opened this week in Frankfurt, figures from a study conducted by the PwC consulting firm added more worry for printed book dealers about the uncertain future of their trade.

According to the study, released Tuesday, demand for e-books is getting ever-larger in Germany. By 2015, the turnover for fiction alone is estimated at over 350 million euros, or 6.3% of the market. By the end of 2010, only some 20 million euros worth of fictional e-books had been sold. Meanwhile, this year the traditional retail book business is once again showing a drop of just about 5%.

"To me, that is a figure that spells a need for reflection," said Gottfried Honnefelder, president of the German Publishers & Booksellers Association.

Nonetheless, he said he was optimistic about the future of bricks and mortar, as book stores fueled by creative new ideas were opening up all over Germany. "My impression is that the time for independent bookstores has come,” he said.

In his opening speech, book fair director Juergen Boos referred to changes happening in the book industry right now as the most significant since the introduction of the printing press. "New players are coming into the sector every day, creating new product ideas and business models. You could call this development the ‘big bang’ of publishing."

The changes were most readily apparent in media targeting of the children's and young adult markets, he said, which is why -- with 1,500 exhibitors and 340 events -- they were a focal point this year at the Frankfurt festival.

Another major highlight this year, Boos said, is the launch of the "Roadmap to Publishing Trends" (in English here).

There are some 7,300 exhibitors at the Frankfurt Book Fair this year – slightly less than last year (7,384). In 2010, there were 7,539 exhibitors. The fair runs until Sunday, October 14.