has a council headed by a district director. From there, the districts are broken down into quarters. Since the changes in city statutes on 1 July 2007 and 1 January 2009, the total number of quarters rose to 152. Economy The Stuttgart area is known for its high-tech industry. Some of its most prominent companies include Mercedes-Benz Group, Porsche, Robert Bosch GmbH, McKesson Europe, Hewlett-Packard, IBM, and Sika AG – all of whom have their world or European headquarters here. Stuttgart is home to Germany's ninth biggest exhibition center, Stuttgart Trade Fair, which lies on the city outskirts next to Stuttgart Airport. Hundreds of SMEs are still based in Stuttgart (often termed Mittelstand), many still in family ownership with strong ties to the automotive, electronics, engineering and high-tech industry. Stuttgart has the highest general standard of prosperity of any city in Germany. Its nominal GDP per capita is €57,100 and GDP purchasing power parity (PPP) per capita is €55,400. Total GDP of Stuttgart is €33.9 billion, of which service sector contributes around 65.3%, industry 34.5%, and agriculture 0.2%. The cradle of the automobile The automobile and motorcycle were purported to have been invented in Stuttgart (by Karl Benz and subsequently industrialized in 1887 by Gottlieb Daimler and Wilhelm Maybach at the Daimler Motoren Gesellschaft). As a result, it is considered to be the starting point of the worldwide automotive industry and is sometimes referred to as the 'cradle of the automobile'. Today, Mercedes-Benz and Porsche both have their headquarters in Stuttgart, as well as automotive parts giants Bosch and Mahle. A number of auto-enthusiast magazines are published in Stuttgart. Science and research and development The region currently has Germany's highest density of scientific, academic and research organisations. No other region in Germany registers so many patents and designs as Stuttgart. 45% of Baden-Württemberg's R&D capacities are concentrated in the Swabian capital. More than 11% of all German R&D costs are invested in the Stuttgart region (approximately 4.3 billion euros per year). In addition to several universities and colleges (e.g. University of Stuttgart, University of Hohenheim, Stuttgart Institute of Management and Technology and several Stuttgart Universities of Applied Sciences), the area is home to six Fraunhofer institutes, four institutes of collaborative industrial research at local universities, two Max-Planck institutes and a major establishment of the German Aerospace Centre (DLR). Financial services The Stuttgart Stock Exchange is the second largest in Germany