The consumer price index measures the cost of a broad number of goods and services.
Even with the month-to-month decline, the price index was up 5.7 percent in December from the same time last year.
A drop in gasoline prices is likely part of the reason for the CPI decline, according to the report. Gas prices declined 9.4 percent in December, down 1.5 percent from the same period last year.
Food prices did increase 0.3 percent, while housing prices increased by 0.8 percent.
