Statistics from the China Association of Metros showed that in 2015, China put in place 44 urban rail transit projects nationwide and 26 cities had rail transit systems in place with an operational length of 3,618 kilometers. Metros accounted for over 73 percent of the overall length. Since May 2013, provincial governments have been responsible for the examination and approval of rail transit projects and a growing number of such projects are springing up nationwide, including some in small cities. Nevertheless, official statistics show that revenues for most metro projects do not cover operating costs. It has become an urgent problem for local governments to collect enough funds for construction and running fees. Experts warned that it would be wise for medium- and small-sized cities to build relatively inexpensive single-track transportation systems based on strict urban planning and in accordance with local circumstances.