A key inflation indicator rose 3.1% faster than expected in April as price pressures mounted in the fast-growing US economy, the Department of Commerce reported on Friday.

The core personal consumption expenditure index should rise 2.9%. Federal Reserve officials consider the measure to be the best measure of inflation, despite observing a number of metrics.

Under its price stability mandate, the Fed considers 2% healthy, although it has pledged to keep the average higher than usual in the interests of promoting full employment.

The index tracks price movements in a wide variety of goods and services and is generally considered to be a more comprehensive measure of inflation because it tracks changes in consumer behavior and has a broader scope than the Department of Labor’s consumer price index. The CPI rose 4.2% in April.

Last month, core PCE rose 0.7%, also faster than the expected 0.6%.

Including volatile food and energy prices, the PCE benchmark index rose 3.6% year-on-year and 0.6% compared with March.

This rise in inflation was accompanied by a sharp slowdown in personal income, which fell by 13.1%. But that was actually less than the 14% estimate. Personal income was up 20.9% in March after the last round of government economic reviews.

Despite the sharp decline in personal income, the savings rate remained high at 14.9%. Consumer spending is estimated to have increased by 0.5%.

Disposable personal income after taxes and other withholding taxes fell 14.6%.

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