U.S. producer prices rose for a third straight month in July, suggesting the drag on inflation from weaker oil prices was easing. The Labor Department said on Friday its producer price index for final demand increased 0.2 percent last month after increasing 0.4 percent in June. An increase of 0.4 percent in services prices, which offset a fall of 0.1 percent in the cost of goods, accounted for the increase in the PPI last month.