With food prices showing a notable decrease, the Labor Department released a report on Tuesday showing that U.S. producer prices fell by slightly more than expected in December. The Labor Department said its producer price index dipped by 0.2 percent in December after falling by 0.8 percent in November. Economists had expected the index to edge down by 0.1 percent. Excluding the drop in food prices as well as a modest decrease in energy prices, the core producer price index inched up by 0.1 percent in December. The increase by the core producer price index, which matched the increase seen in the previous month, came in below economist estimates for 0.2 percent growth.