A free trade agreement (FTA) signed with the United States will help South Korea\'s economy expand by more than 5 percent in the long term as it will lead to more exports by reducing trade barriers, a report showed Friday. The Korea-U.S. FTA, known as KORUS FTA, was signed in 2007 but the deal was supplemented in late December with minor modifications that mostly dealt with the auto industry. The agreement has been awaiting approval from the legislatures of the two countries.