Revenue at Hachette Book Group rose 5.4% in the first quarter ended March 31, over the comparable period last year, parent company Lagadere reported. Total sales for the Lagardere publishing group increased 0.4%, to 442 million euros.

Lagardere said revenue for the total publishing group was affected by a negative 23 million euros exchange rate, which was offset by the acquisitions of Brainbow, Bookouture, Summerside, and Jessica Kingsley. The company also noted that e-books’ share of revenue fell again in the quarter, dropping from 10% in the first period of 2017 to 9.1% in the most recent quarter.

Within the U.S., HBG CEO Michael Pietsch said the first quarter gains “came from many places: #1 bestselling books by HBG house authors James Patterson, David Baldacci, Douglas Preston Lincoln Child, and Brad Meltzer.” He added that backlist hits also had an impact, citing You Are a Badass, Obama: An Intimate Portrait and Pachinko. Breakout bestseller such as Russian Roulette and Dear Madam President, also contributed to the sales gain, Piestch said

Pietsch was optimistic about prospects for the second quarter, pointing to the publication of the publisher’s “biggest book of the year,” James Patterson and Bill Clinton’s The President is Missing (which Knopf is co-publishing). The book is due out June 4.