By John S. McClenahen A 7.4% increase in the price of U.S. petroleum imports in December was largely responsible for last month's overall 0.7% rise in the U.S. Import Price Index, says the U.S. Labor Department's Bureau of Labor Statistics. The index had fallen 1% in November. December's increase in petroleum prices was the largest since a 12.7% rise in April 2002. In contrast to the import index, the U.S. Export Price Index fell 0.2% in December, with prices for both agricultural and non-agricultural U.S. exports declining.