U.S. wholesale prices fell unexpectedly in September on lower energy costs, as inflation remains contained amid signs of a broad but slow economic recovery. The Labor Department said Tuesday that its producer price index (PPI) fell 0.6 percent last month, in contrast to economists' expectation of a flat reading. The PPI rose sharply in August. In the 12 months ending in September, the index fell 4.8 percent, more than expected and the 10th consecutive month of annual declines. September's “core” PPI, which excludes volatile energy and food costs, fell 0.1 percent. In the 12 months ending last month, core PPI rose 1.8 percent. Both figures were below analysts' expectations. The PPI tracks the prices of goods before they reach store shelves, and it is considered an early reading on price trends. It has been volatile in recent months, reflecting wide swings in energy costs. September's decline in wholesale prices was largely driven by gasoline, which fell 5.4 percent, and heating oil, which dropped 9.8 percent. Those changes followed steep rises in August, when wholesale gasoline prices jumped 23 percent. Energy prices have fallen steeply over the past year, though they have started to rise again this month. Wholesale gasoline prices have tumbled 37.5 percent from record highs reached last summer, when retail prices surpassed $4 per gallon (3.8 liters). Tuesday's report follows a mild consumer inflation report from the Labor Department last week. Consumer prices rose 0.2 percent in September and have fallen 1.3 percent over the past 12 months. Excluding energy and food costs, core consumer prices also rose 0.2 percent last month and rose 1.5 percent over the past year. Rising unemployment, nervous consumers, and tight credit have kept prices contained, enabling the Federal Reserve to keep short-term interest rates at record lows, where they are expected to remain until sometime next year. --SPA