The slump in crude oil prices pushed U.S. inflation last month to its weakest annual rate since the financial crisis.
Figures from the U.S. Department of Labor showed the U.S. consumer price index climbed 0.8% in December from a year earlier, as energy costs slid and the average price of gasoline declined by more than $1 per gallon.
The headline reading, a 10th of a point ahead of Wall Street forecasts, was a low since October 2009.
Excluding more volatile categories including energy and food, the monthly report showed a 1.6% year-on-year rise, below economist expectations.
Investors are closely scrutinizing inflation figures as the Federal Reserve prepares to begin tightening monetary policy. Lackluster wage pressures at year's end and cooling inflation could delay the first rate hike, several economists have argued.
The Fed's stated measure of inflation is the monthly price inflation measure for personal consumption expenditures, reported by the Commerce Department.
