The nation' trade surplus in January plummeted 30.7 percent from a year earlier to 522.6 billion yen, marking the 10th straight month of year-on-year decline, the Finance Ministry said Wednesday. Rising oil prices helped imports, particularly those from the rest of Asia, outpace an expansion in exports, resulting in the lowest surplus in two years, according to the preliminary customs-cleared figures on merchandise trade. The surplus is expected to continue shrinking for the time being because, given global economic situations, imports are expected to grow faster than exports, a ministry official said. Both exports and imports increased from a year earlier for the third month in a row. Exports edged up 1.7 percent to 3.51 trillion yen. Exports of ships and electronics parts, such as semiconductors, marked double-digit growth. But automobile exports, mainly to the United States and the European Union, fell more than 20 percent. Imports increased 10.7 percent to 2.99 trillion yen, with crude oil doubling and oil products up 61 percent. Oil imports pushed up the total value of imports by 6.4 percent. Oil prices averaged $25.7 a barrel in the month, up 127 percent from January 1999. The yen averaged 103.75 to the dollar, up 10 percent from a year earlier. A stronger yen usually helps make Japanese goods more expensive abroad and imports to Japan cheaper. On a regional basis, the trade surplus with the U.S. slipped 1.9 percent to 477.8 billion yen, the second consecutive month of year-on-year decrease. Exports, including cars and office equipment like computers, dropped 4.4 percent, and imports, including office equipment, fell 6.4 percent. Exports to the rest of Asia advanced 15 percent while imports from the region surged 19.2 percent. The resulting surplus declined 20.8 percent to 94 billion yen. With the 15-member EU, the trade surplus plunged 20.3 percent to 218.9 billion yen. Exports fell 7.4 percent and imports rose 1.5 percent.