The nation's current account surplus rose 43.6 percent in August from a year earlier to 1.158 trillion yen, the Finance Ministry said in preliminary statistics released Thursday.It was the 17th consecutive month of growth for the broadest gauge of trade in goods and services and some unilateral transfers.The increase was mainly attributed to a 21 percent increase in the merchandise trade surplus, which came to 1.091 trillion yen. The domestic economic slump and lower international oil prices pushed imports down, while exports rose only slightly, due to the recession in Asia, the ministry said.This trend is unlikely to change soon, although imports may rise when Japan's pump-priming measures begin taking effect, a ministry official said. The rise of the yen against the dollar could push up the trade surplus in the short term, he added.Exports went up 0.7 percent to 3.843 trillion yen, with vehicle engines up 29.4 percent and iron and steel up 16.5 percent. Electronic parts such as semiconductors fell 6.8 percent.Imports declined 5.5 percent to 2.752 trillion yen, with crude oil down 21.6 percent as its price dropped 30.3 percent from a year earlier. Wood products fell 32.5 percent, while airplanes increased 55.4 percent.