<Tr> <Th> Area served </Th> <Td> Worldwide, 633 cities </Td> </Tr> <Tr> <Th> Key people </Th> <Td> <Ul> <Li> Dara Khosrowshahi (CEO) </Li> <Li> Thuan Pham (CTO) </Li> <Li> David Richter (SVP, Business) </Li> <Li> Ursula Burns (Board of Directors) </Li> <Li> John Thain (Board of Directors) </Li> </Ul> </Td> </Tr> <Ul> <Li> Dara Khosrowshahi (CEO) </Li> <Li> Thuan Pham (CTO) </Li> <Li> David Richter (SVP, Business) </Li> <Li> Ursula Burns (Board of Directors) </Li> <Li> John Thain (Board of Directors) </Li> </Ul> <Li> Dara Khosrowshahi (CEO) </Li>

How many uber drivers are there in usa