The board of German postal and logistics group Deutsche Post DHL Juergen Gerdes, Ken Allen, CFO Melanie Kreis, CEO Frank Appel and John Gilbert pose for a picture before the annual news conference of DHL in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

The board of German postal and logistics group Deutsche Post DHL Juergen Gerdes, Ken Allen, CFO Melanie Kreis, CEO Frank Appel and John Gilbert pose for a picture before the annual news conference of DHL in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, poses with a zero emissions statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, poses with a zero emissions statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, attends the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, speaks at the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, walks behind a zero emissions statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, poses with a zero emissions statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, walks behind a zero emissions statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, poses next to a statue to promote the company's "mission 2050 - zero emissions" goal during the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL uncurtains a statue to promote the company's 'mission 2050 - zero emissions' goal during company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL speaks at the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL speaks at the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL poses before the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL poses before the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL poses before the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL and CFO Melanie Kreis arrive for the company's annual news conference in Bonn, Germany March 8, 2017. REUTERS/Wolfgang Rattay

People are reflected between glass facades of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 5, 2013. REUTERS/Wolfgang Rattay/File Photo GLOBAL BUSINESS WEEK AHEAD PACKAGE - SEARCH 'BUSINESS WEEK AHEAD NOV 7' FOR ALL IMAGES

Parcels are scanned at a distribution centre of German postal and logistics group Deutsche Post DHL in Obertshausen, Germany June 15, 2016. REUTERS/Ralph Orlowski/File Photo

Frank Appel, CEO of German postal and logistics group Deutsche Post DHL looks out of a StreetScooter E-car in Bonn May 21, 2013. REUTERS/Wolfgang Rattay /File Photo

Frank Appel, CEO of German postal and logistics group Deutsche Post (DHL) poses in front of a StreetScooter E-car in Bonn May 21, 2013. REUTERS/Wolfgang Rattay/File Photo

Frank Appel, CEO of German postal and logistics group Deutsche Post DHL poses in front of a StreetScooter E-car and other E-cars in Bonn May 21, 2013. REUTERS/Wolfgang Rattay/File Photo

German postal and logistics group Deutsche Post DHL CEO Frank Appel poses outside the company's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel poses outside the company's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CFO Lawrence Rosen attends annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel attends annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel attends annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel appears on a video screen next to a truck with the DHL logo during the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel poses next to a scale model of high-speed, solar driven, DHL delivery boat of the future, prior to the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel poses next to a scale model of high-speed, solar driven, DHL delivery boat of the future, prior to the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel attends annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel addresses the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL CEO Frank Appel attends annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL board members Juergen Gerdes and Ken Allen (R) take selfies prior to the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL board members CFO Lawrence Rosen and CEO Frank Appel (R) pose prior to the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

German postal and logistics group Deutsche Post DHL board members (L-R) CFO Lawrence Rosen Melanie Kreis, CHO Melanie Kreis, CEO Frank Appel, Juergen Gerdes, post ecommecre member of board, John Gilbert, supply chain member of board and Ken Allen, express member of board, pose prior to the annual news conference at DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

Packages are seen at the German postal and logistics group Deutsche Post DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

General view of the exterior of the German postal and logistics group Deutsche Post DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

General view of the exterior of the German postal and logistics group Deutsche Post DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

General view of the exterior of the German postal and logistics group Deutsche Post DHL's innovation centre in Troisdorf near Bonn, western Germany, March 9, 2016. REUTERS/Wolfgang Rattay

A Deutche Post sign adorns the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post sign adorns the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post sign adorns the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post and DHL sign stands in front of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post sign stands in front of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post sign stands in front of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

A Deutche Post sign stands in front of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS LOGO)

Workers are reflected between glass facades of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Workers are reflected between glass facades of the Bonn Post Tower, the headquarters of German postal and logistics group Deutsche Post DHL in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, attends the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS HEADSHOT)

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, attends the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS HEADSHOT)

Melanie Kreis, head of Human Resources and member of the Board of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS HEADSHOT)

Melanie Kreis, head of Human Resources and member of the Board of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Melanie Kreis, head of Human Resources and member of the Board of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Melanie Kreis, head of Human Resources and member of the Board of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Frank Appel, Chief Executive Officer of German postal and logistics group Deutsche Post DHL, arrives for the company's annual news conference in Bonn March 11, 2015. REUTERS/Wolfgang Rattay (GERMANY - Tags: BUSINESS)

Workers load trucks with parcels at the new distribution centre of the German postal and logistics group Deutsche Post DHL in Berlin November 12, 2013. Deutsche Post posted a better-than-expected rise in quarterly operating profit as earnings at its domestic mail and international courier units helped to offset adverse currency moves. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS BUSINESS)

A worker unloads a truck at the new distribution centre of the German postal and logistics group Deutsche Post DHL in Berlin November 12, 2013. Deutsche Post posted a better-than-expected rise in quarterly operating profit as earnings at its domestic mail and international courier units helped to offset adverse currency moves. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS BUSINESS)