SEOUL (AFP) - South Korean exports rose by double digits in March for a fifth straight month, according to official figures issued Thursday, as demand in major markets continued to improve. Exports were worth 37.68 billion dollars last month, up 35.1 percent year-on-year, while imports jumped 48.4 percent to 35.49 billion, the Ministry of Knowledge Economy said. The March trade balance of 2.19 billion dollars compares to a revised 2.08 billion dollar surplus recorded for February. The ministry, releasing preliminary figures based on the March 1-20 period, said exports to China rose by 47.5 percent year-on-year; to Japan by 34.3 percent; to the European Union by 8.4 percent; to the United States by 30.4 percent; and to Southeast Asian nations by 61.8 percent. South Korean shipbuilders said separately the combined value of orders received in the first quarter jumped more than five-fold from a year earlier. Orders won by Hyundai Heavy Industries, Samsung Heavy Industries, Daewoo Shipbuilding and Marine Engineering and STX Offshore and Shipbuilding totalled 5.49 billion dollars in January-March compared with 962 million for the same period last year.