Led by a large decline in energy prices, U.S. consumer prices were unchanged in April after seasonal adjustments and have fallen 0.7% in the past 12 months, the largest decline in 54 years, the Labor Department reported Friday. The decline in the consumer price index has sparked concerns about deflation in the United States. However, core inflation - which excludes volatile food and energy prices - has not declined. In the past year, the core CPI is up 1.9%. In April, the seasonally adjusted core CPI rose 0.3%, boosted by a 9.3% increase in tobacco prices. Excluding tobacco, the CPI fell 0.1% and the core CPI rose 0.1%.