Volkswagen CEO Martin Winterkorn addresses the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

German Chancellor Angela Merkel (3rd L) and British Prime Minister David Cameron (1st L) view a model of an Audi driverless car during the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

British Prime Minister David Cameron addresses the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

A band performs during the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

German Chancellor Angela Merkel (1st L) views a model of an Audi driverless car during the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

British Prime Minister David Cameron attends the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

British Prime Minister David Cameron addresses the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

German Chancellor Angela Merkel addresses the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

German Chancellor Angela Merkel (L) and British Prime Minister David Cameron attend the opening ceremony of the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)

A worker rests in front of a poster at the CeBIT tech fair in Hanover, Germany, March 9, 2014. German Chancellor Angela Merkel and British Prime Minister David Cameron jointly opened CeBIT, one of the world's largest IT fairs, in western German city of Hanover on Sunday. (Xinhua/Zhang Fan)