A sharp drop in the cost of gasoline and food pushed down overall U.S. producer prices in April.

The Labor Department says its producer price index fell 0.4 percent last month after rising 0.2 percent in March. But even excluding volatile food and energy categories, the core index slipped 0.2 percent last month, brought down in part by lower shipping costs.

The index measures prices of goods and services before they reach consumers.

Over the past year, wholesale prices have dropped 1.3 percent, the most since Labor revamped the index in late 2010.

Federal Reserve officials are weighing whether to raise short-term interest rates for the first time in more than six years. They want to see annual inflation heading toward 2 percent, sign of a healthier economy.