April 16, 2012. China will pass the U.S. in 2013 as the biggest user of tankers carrying oil at sea as Asian imports travel over longer distances and fewer cargoes go to the world's biggest economy. Tanker use based on ton- mile demand, which multiplies cargo size by voyage length, is rising for China and dropping for the U.S. Chinese tanker usage will gain 18 percent to 2.43 trillion ton-miles by 2013 as the U.S. falls 13 percent to 2.36 trillion. China will account for 25 percent of oil-tanker demand by 2015, against 19 percent for the U.S. U.S. seaborne imports of crude will decline to 7.6 million barrels a day, the lowest level since 1995, from 8.3 million.