The Consumer Price Index rose 3 percent in December from a year earlier, although prices remained flat from November, the U.S. Commerce Department said. Core prices, which exclude energy and food items, were up 2.2 percent on an annual basis after rising 0.1 percent in December and 0.2 percent in November. The 2.2 percent January-to-December gain follows a 0.8 percent gain in core prices in 2010, which is a record low. The total index has been offset for three months running by lower energy costs for consumers. Prices for energy items dropped 1.3 percent month-to-month in December following a 1.6-percent drop in November and a 2-percent drop in October. On an annual basis, the price of energy items is up 6.6 percent, with gasoline prices up 0.9 percent and fuel oil prices up 18 percent. Overall, that is a \"deceleration\" from 2010, when prices on the year rose 7.7 percent, the department said. Food prices in December rose 0.2 percent after a 0.1 percent gain in the previous two months. On an annual basis, food costs are up 4.7 percent, a far sharper climb than the previous year, 2010, when food prices rose 1.5 percent January through December.