 Complete the following phrase:  Drivers from 40 countries have entered a World Championship race. The United Kingdom is the most heavily represented with 164 drivers. Second is the United States with 158; between 1950 and 1960 the American Indianapolis 500 race, rarely contested by drivers from outside the United States, was part of the World Drivers Championship. A total of 36 American drivers have started World Championship races sanctioned by the FIA. Third is Italy with 99. Nine of these countries were represented in the very first race, the 1950 British Grand Prix, and the most recent newly represented country is Indonesia, with Rio Haryanto making his debut at the 