U.S. consumer prices rose last month by the most since June, driven up by higher gas prices, but excluding energy, inflation was tame. The Labor Department said Thursday that the consumer price index rose a seasonally adjusted 0.3 percent in December, after a flat reading the previous month. Prices increased 1.5 percent in 2013, down from 1.7 percent in 2012. That's below the Federal Reserve's target of 2 percent. Grocery prices were flat, held down by the biggest drop in fruit and vegetable prices in five years.