US producer prices increased further in October, leading to the largest annual gain in four years and supporting expectations that the Federal Reserve could continue raising interest rates after next month's widely expected hike. The Producer Price Index for final demand rose 0.3% last month after an upwardly revised 1.4% surge in September, the Labor Department's Bureau of Labor Statistics said on Friday. Economists polled by Reuters had forecast the PPI climbing 0.4% after vaulting 1.3% in September. Producer prices last month were lifted by a 0.5% rise in goods, mostly food and basic organic chemicals. Services increased 0.2%, advancing for the fifth straight month.