The New York City Subway is the largest subway system in the world when measured by number of stations (472),[34] and the eighth-largest[35] when measured by annual ridership (1.76 billion passenger trips in 2015).[36] It is the second-oldest subway system in the United States after the rapid transit system in Boston. In 2002, an average 4.8 million passengers used the subway each weekday. During one day in September 2005, 7.5 million daily riders set a record for ridership.