BERLIN, April 4 (Xinhua) -- Strong e-commerce sales have boosted the earnings of the German mail-order business Otto Group, the company informed press on Wednesday citing preliminary earnings figures.

Revenue at the family business grew by nearly seven percent to 13.4 billion euros (16.5 billion U.S. dollars) in the 2017-18 fiscal year, allowing Otto to comfortably defend its title as Europe's largest mail order company. More than half of the total revenue were achieved through the online unit of Otto where sales soared by 7.8 percent to 7.8 billion euros.

"In order to achieve out revenue goal of 17 billion euros by 2020 on a comparable basis we have to grow by around five percent each year. During the past year we more than achieved this task and expect further high revenue growth in 2018-19 as well," a statement by Otto chief executive officer (CEO) Alexander Birken read.

The flagship brand Otto grew thanks to a web of new partnership with external trading entities and producers, including the fast-growing fashion start-up About You. Additionally, Otto's services business in cooperation with the logistics company Hermes also experienced a positive year.

Founded in 1949, Otto Group is based in the Northern German port city of Hamburg and employed a total of 49,787 staff in 2017.