Railroads in Azerbaijan (not including industrial lines) extend some 2,125 km (1,320 mi), with Baku as the hub. In 2002, the highway system totaled 36,700 km (22,805 mi), of which 31,800 km (19,760 mi) were paved. Azerbaijan's major port is at Baku. In 2002 the merchant marine had 54 ships (1,000 GRT or over), totaling 246,051 GRT. Ships from the Caspian fleet have called at some 125 ports in over 30 countries. In 2001 airports numbered 52, of which 9 had paved runways. There are flights from Baku's Bina Airport to more than 70 cities of the former Soviet Union. In 2001, 543,800 passengers were carried on scheduled domestic and international airline flights.