The Fed’s favorite price index rose again in June, as consumer spending came in strong.

The Federal Reserve’s favorite inflation index climbed 4 percent in June compared with a year earlier, as a rebounding economy and strong demand for goods and services helped to push prices higher.

The gains in the Personal Consumption Expenditures inflation index were the fastest since 2008, but in line with economists’ expectations. That rapid pace is not expected to last, but how much and how quickly it will fade is the economic question of the moment.

Inflation has been surprisingly rapid this year. Economists knew prices would post strong increases as they were measured against weak figures from 2020, when costs for many common purchases slumped. But the jump has been more intense than most were expecting.

That’s partly because supply bottlenecks have emerged across the reopening of the U.S. economy. Computer chip shortages pushed up the prices of electronics and delayed automobile production, causing used car prices to surge. Employers are struggling to hire back workers fast enough to meet returning demand, and prices for restaurant meals and some other services have begun to move higher.

The same release containing the inflation data showed that spending remained stronger than economists had expected, climbing by 1 percent in June compared with the prior month, more than the 0.7 percent pop anticipated in a Bloomberg survey. Adjusting for inflation, spending was up 0.5 percent.

Even as demand remains robust, June’s inflation data may be a high point. Last year’s low figures are fading from the data, and many economists expect the rapid pace of price gains to begin to moderate in the coming months.

On a monthly basis, inflation climbed 0.5 percent from May to June, slightly less than the 0.6 percent economists in a Bloomberg survey had expected. The core inflation index, which strips out volatile food and fuel, climbed 3.5 percent over the past year.

Higher prices are taking a bite out of workers’ paychecks. Income after taxes fell 0.5 percent June, accounting for the impact of inflation. Over the past year, inflation has more than offset a modest rise in after-tax income.

How quickly inflation will fall back to the Fed’s 2 percent target, which it tries to hit on average over time, is increasingly uncertain. It is hard to know how quickly the supply chain snarls that have complicated the price picture so far this year will clear up, or whether new ones will emerge. Climbing coronavirus cases around the world could make for continued disturbances in global production and shipping routes, ones that will hit just in time for back-to-school and the holiday shopping season.