The Staten Island Ferry is the world's busiest ferry route, carrying approximately 20 million passengers on the 5.2-mile (8.4 km) route between Staten Island and Lower Manhattan and running 24 hours a day. Other ferry systems shuttle commuters between Manhattan and other locales within the city and the metropolitan area.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): How many passengers ride the Staten Island Ferry annually?
20 million