Clinical and Experimental Medicine, which was the largest transplant center in Europe as of 2019. Universities seated in Prague (see section Colleges and Universities) also represent important centres of science and research activities. , there were 13,000 researchers (out of 30,000 in the country, counted in full-time equivalents), representing a 3% share of Prague's economically active population. Gross expenditure on research and development accounted for €901.3 million (41.5% of country's total). Some well-known multinational companies have established research and development facilities in Prague, among them Siemens, Honeywell, Oracle, Microsoft and Broadcom. Prague was selected to host administration of the EU satellite navigation system Galileo. It started to provide its first services in December 2016 and full completion is expected by 2020. Transport , Prague's transport modal share by journey was 52% public transport, 24.5% by car, 22.4% on foot, 0.4% by bike and 0.5% by aeroplane. Public transportation The public transport infrastructure consists of the heavily used Prague Integrated Transport (PID, Pražská integrovaná doprava) system, consisting of the Prague Metro (lines A, B, and C – its length is with 61 stations in total), Prague tram system, Prague buses, commuter trains, funiculars, and seven ferries. Prague has one of the highest rates of public transport usage in the world, with 1.2 billion passenger journeys per year. Prague has about 300 bus lines (numbers 100–960) and 34 regular tram lines (numbers 1–26 and 91–99). There are also three funiculars, one on Petřín Hill, one on Mrázovka Hill and a third at the Zoo in Troja. The Prague tram system now operates various types of trams, including the Tatra T3, newer Tatra KT8D5, Škoda 14 T (designed by Porsche), newer modern Škoda 15 T and nostalgic tram lines 23 and 41. Around 400 vehicles are the modernized T3 class, which are typically operated coupled together in pairs. The Prague tram system is the twelfth longest in the world (142 km) and its rolling stock consists of 857 individual cars, which is the third largest in the world behind Moscow and Budapest. The system carries more than 360 million passengers annually, the highest tram patronage in the world after Budapest, on a per capita basis, Prague has the second highest tram patronage after Zürich. All services (metro, tramways, city buses, funiculars and ferries) have a common ticketing system that operates on a proof-of-payment system. Basic transfer tickets can be bought for 30 and