WASHINGTON (AP) Inflation soared over the past year at its highest rate in four decades, hammering Americas consumers, wiping out pay raises and reinforcing the Federal Reserves decision to begin raising borrowing rates across the economy.

The Labor Department said Thursday that consumer prices jumped 7.5% last month compared with 12 months earlier, the steepest year-over-year increase since February 1982. Shortages of supplies and workers, heavy doses of federal aid, ultra-low interest rates and robust consumer spending combined to send inflation accelerating in the past year.

When measured from December to January, inflation was 0.6%, the same as the previous month and more than economists had expected. Prices had risen 0.7% from October to November and 0.9% from September to October.

There are few signs that inflation will slow significantly anytime soon. Most of the factors that have forced up prices since last spring remain in place: Wages are rising at the fastest pace in at least 20 years. Ports and warehouses are overwhelmed, with hundreds of workers at the ports of Los Angeles and Long Beach, the nations busiest, out sick last month. Many products and parts remain in short supply as a result.

The steady surge in prices has left many Americans less able to afford food, gas, rent, child care and other necessities. More broadly, inflation has emerged as the biggest risk factor for the economy and as a serious threat to President Joe Biden and congressional Democrats as midterm elections loom later this year.

The Fed and its chair, Jerome Powell, have pivoted sharply away from the ultra-low-interest rate policies that the Fed pursued since the pandemic devastated the economy in March 2020. Powell signaled two weeks ago that the central bank would likely raise its benchmark short-term rate multiple times this year, with the first hike almost surely coming in March. Investors have priced in at least five rate increases for 2022.

Over time, those higher rates will raise the costs for a wide range of borrowing, from mortgages and credit cards to auto loans and corporate credit. For the Fed, the risk is that in steadily tightening credit for consumers and businesses, it could trigger another recession.

Many large corporations, in conference calls with investors, have said they expect supply shortages to persist until at least the second half of this year. Companies from Chipotle to Levis have also warned that they will likely raise prices again this year, after having already done so in 2021.

Chipotle said its increased menu prices 10% to offset the rising costs of beef and transportation as well as higher employee wages. And the restaurant chain said it will consider further price increases if inflation keeps rising.

We keep thinking that beef is going to level up and then go down, and it just hasnt happened yet, said John Hartung, the companys chief financial officer.

Executives at Chipotle, as well as at Starbucks and some other consumer-facing companies, have said their customers so far dont seem fazed by the higher prices.

Levi Strauss & Co. raised prices last year by roughly 7% above 2019 levels because of rising costs, including labor, and plans to do so again this year. Even so, the San Francisco-based company has upgraded its sales forecasts for 2022.

Right now, every signal were seeing is positive, CEO Chip Bergh told analysts.

Many small businesses, which typically have lower profit margins than larger companies and have struggled to match their sizable pay raises, are also raising prices. The National Federation for Independent Business, a trade group, said it found in a monthly survey that 61% of small companies raised their prices in January, the largest proportion since 1974 and up from just 15% before the pandemic.

More small business owners started the new year raising prices in an attempt to pass on higher inventory, supplies and labor costs, said Bill Dunkelberg, the NFIBs chief economist. In addition to inflation issues, owners are also raising compensation at record-high rates to attract qualified employees to their open positions.

Those pay gains could eventually force additional price hikes as companies seek to cover the costs of the higher wages.

In the past year, sharp increases in the costs of gas, food, autos and furniture have upended many Americans budgets. In December, economists at the University of Pennsylvanias Wharton School estimated that the average household had to spend $3,500 more than in 2020 to buy an identical basket of goods and services.

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AP Business Writers Dee-Ann Durbin in Detroit and Anne DInnocenzio in New York contributed to this report.