The cost of living in the U.S. increased a larger-than-forecast 0.6 percent after a 0.3 percent gain in December, the Labor Department reported Wednesday.

Compared with the same month last year, costs paid by Americans for goods and services rose 2.5 percent.

Higher costs for gasoline, apparel and new cars indicate that inflation is gathering momentum. Core inflation increased 2.3 percent from January 2016.

Bloomberg reported Wednesday a comment made before the report by Sam Bullard, senior economist at Wells Fargo Securities in Charlotte, North Carolina: “CPI inflation has been steady in recent months amid rising energy prices.”

A 7.8 percent jump in the cost of gasoline accounted for about half of the increase in the January CPI.

“After the past couple years, the transitory nature of the dip in inflation due to the decline in energy prices has come to fruition,” Bullard said.

In her testimony before Congress on Tuesday, Federal Reserve Chair Janet Yellen said that more interest-rate increases will be appropriate if inflation picks up and the labor market remains tight.

Wednesday’s report from the Labor Department showed energy costs increased 4 percent from a month earlier. Food prices rose 0.1 percent.

Energy prices in the South rose 3.2 percent and food prices rose 0.4 percent in January. The consumer price index for the South rose 0.5 percent over the month. These numbers are not seasonally adjusted, so the change may reflect seasonal influences.

The U.S.’s core CPI measure rose 0.3 percent this month, the most in five months. Bloomberg called for the core index to rise 0.2 percent from the previous month, and 2.1 percent from the prior year.

Over the last 12 months, the South’s core index, which excludes volatile food and fuel costs, increased 2.2 percent, reflecting price increases for shelter and medical care.

The CPI is the broadest of three price gauges from the Labor Department because it includes all goods and services, including prices consumers pay for medical visits, airline fares, movie tickets and rents. The other two measures are import costs and producer prices.