PLANO, Texas (AP) - J.C. Penney says a key sales barometer rose in October for the first time in nearly two years. Its stock climbed in Thursday premarket trading. Sales at stores open at least a year edged up 0.9 percent last month - the first increase since December 2011. This metric is a key indicator of a retailer's health, because it measures growth at ongoing locations by excluding results from stores recently opened or closed. In September, the figure fell 4 percent for the Plano, Texas company. CEO Mike Ullman said in a statement that the October increase came despite the federal government shutdown and tough consumer environment. J.C. Penney Co. said shoppers responded well to promotions and better inventory levels. Online sales climbed 37.6 percent from a year ago.