Porsche AG, with headquarters in Stuttgart-Zuffenhausen, is one of the most profitable car makers in the world. In 2016, Porsche delivered 237,778 vehicles of the 911, Cayenne, Macan, Panamera, 718 Boxster and Cayman models to customers worldwide. That was 6 per cent more than the year before. Thereby, the sports car manufacturer's operating profit amounted to 3.9 billion euros, up 14 per cent from the previous year's comparative figure. Porsche operates plants in Stuttgart and Leipzig as well as a development centre in Weissach. The sports car maker employs about 28,000 people (as at March 31, 2017). The Porsche principle of getting the most out of all opportunities stems from the race track and is embodied in every vehicle. Thanks to its high quality standards, 70 per cent of all Porsches ever built are still on the street today.