1 of 2 | People pump gas at a gas station in Washington, D.C., on May 30. Gas prices are up 50% since the war between the United States and Iran. High energy costs account for 60% of the increase in the consumer price index for all items in May, the Bureau of Labor Statistics reported Wednesday. Photo by Bonnie Cash/UPI | License Photo

June 10 (UPI) -- Consumer prices for the year ending in May rose by 4.2%, the fastest rate of inflation in three years, the Bureau of Labor Statistics reported Wednesday.

A 3.9% increase in the index for energy for the month bolstered the rapid acceleration of inflation. Energy's index rose by 3.8% in April and 10.9% in March, after the United States launched the Iran war.

For the month, the consumer price index increased at a seasonally adjusted 0.5% rate.

The increase in the energy index accounted for 60% of the monthly all-items increase, the bureau said.