Wholesale prices in the United States declined for a third month in November, reflecting lower costs for energy and cars. The 0.1 percent drop in the producer-price index followed a 0.2 percent dip the prior month, a Labor Department report showed today. The median estimate in a Bloomberg survey of 77 economists called for no change. The so-called core measure, which excludes food and energy, rose 0.1 percent. Prices of goods and materials used in the earlier stages of production fell for a second month as slow improvement in global markets limited demand. Scant signs of accelerating inflation indicate Federal Reserve policy makers meeting next week have more room to maintain their unprecedented $85 billion in monthly asset purchases in order to help spur the expansion.