High-speed railway (HSR) in China is officially defined as passenger-dedicated railways designed to carry multiple unit trains at speeds of 250–350 km/h (155–217 mph).  The country's HSR network, which in 2016 extended to 29 of the country's 33 provincial-level administrative divisions and exceeded 22,000 km (14,000 mi) in total length, accounted for about two-thirds of the world's high-speed rail tracks in commercial service. The world's longest HSR network is also the most extensively used, with 1.44 billion trips delivered in 2016. With a total cumulative number of trips at 7 billion in 2017.