Hyundai Motor Co., South Korea\'s leading automaker, said Monday that its 2011 sales increased 12.3 percent from a year earlier, propelled mainly by strong overseas demand for its vehicles. The carmaker said it sold more than 4.05 million vehicles overall last year, up from 3.60 million units tallied in 2010. It said the double digit sales growth can be attributed to strong overseas demand that shot up 14.2 percent on-year to over 3.36 million units. Domestic sales, also moved up 3.6 percent to 683,570 units.