Source: New York Times, http://www.nytimes.com/2009/02/04/us/04transit.html?_r=1&em

Source of Revenue for Some American Transit Systems, 2008

No public transit system in the world generate enough revenue from fares to cover operating expenses, particularly in North America. New York is the transit system which is the "closest" to be self financed, but the share of revenue coming from fare collection still account to only 52% of total revenue. Subsidies, such as toll revenues, make up for the remaining share. For other transit systems, the share of fares is even lower, in the range of 20% to 30%. From a financial perspective, public transit is unsustainable.