Hachette Book Group parent company Lagardère Publishing reported Friday that HBG revenues for the first half of 2015, down 7.8% from 2014. HBG CEO Michael Pietsch blamed the drop on “a tough comparison” to strong early 2014 sales and—in a reference to its new sales agreement with Amazon—pointed to a slowdown in e-book sales “due to e-tailers no longer discounting many e-books at a loss.”

In the first half of 2015, U.S. e-books represented 24% of net trade sales, down from 29% at the end of June 2014. The drop was due to a lighter schedule of titles and, Lagardère said, “the implementation of the agreement with Amazon.”

In 2014 HBG revenues declined 4.8% from 2013, reflecting Hachette’s battle with Amazon over terms, strong sales in 2013 and a decline (19%) in e-book sales in the 4th quarter of 2014.

Nevertheless, HBG reported 87 print bestsellers and 15 e-book bestsellers for the period. Piestch reported “major successes” such as Dan Santat’s Beekle, which won a Caldecott Medal, and Minions tie-in titles (attached to the animated feature film), which have shipped more than 2 million copies. The audio version of Malala Yousafzai’s I Am Malala, won a Grammy and other 2015 HBG bestsellers include David Baldacci’s Memory Man, James Patterson’s The 14th Deadly Sin and Dana Perino’s And The Good News Is.

In France, Lagardère Publishing reported sales at Hachette Livre were up 3%. In the U.K., sales were down 3.5% due to a lighter release schedule than first half 2014. Overall, Lagardère Publishing reported sales of €3.304 billion in the first half of the year, up 2.9% over the same period last year. Lagardère’s EBIT (operating profit) of €122 million is up 11% on first half 2014.

In the U.S., Pietsch anticipates an “exceptionally strong" second half of the year, pointing to upcoming of releases such as Whoopi Goldberg’s Whoopi’s Big Book Book of Relationships, Nicholas Sparks’ See Me, former New York City Police Commissioner Ray Kelly’s Vigilance, a LEGO graphic novel, and Douglas Preston and Lincoln Child’s Crimson Shore.

Correction: An earlier version of this story incorrectly noted that the audio edition of I Am Malala won an Emmy. The audiobook actually won a Grammy Award.