North Korea swung to a current account surplus in 2011 for the first time in recent decades thanks to increased trading with China, a U.S. economist said Tuesday. \"In all likelihood, North Korea has run current account deficits for most of its history, however, on our calculation, largely on the back of expanding trade with China, the current account went into a surplus in 2011,\" said Marcus Noland, a senior fellow at Washington-based Peterson Institute for International Economics, in a posting to the institute\'s Web site.