The local inflation rate rose to 4 percent year-over-year in April, the fastest rate in a decade, according to federal data recently released.

The Bureau of Labor Statistics reported May 10 that the consumer price index for Los Angeles and Orange counties rose by 0.4 percent in April to an index reading of 265 compared to March and was 4 percent higher than the index for April of last year. The national year-over-year inflation rate for April was 2.5 percent.

The index is calculated by comparing current prices for various consumer products to a three-year average from 1982-1984, which the agency assigned as the base period with a value of 100.

The last time the local year-over-year inflation rate topped 4 percent was in the summer of 2008 when it peaked at 5.7 percent, thanks to a spike in gasoline prices as the price for a barrel of oil briefly hit $145.

Similarly, the current year-over-year increase was driven by an 11.5 percent rise in energy prices – chiefly the cost of gasoline. The price for a barrel of crude oil last month topped $70 a barrel for the first time in more than three years. Also, the price of gasoline at the pump is about $1 higher in the Los Angeles area than the national average, thanks to a limited supply of California’s unique required fuel blend and a 12-cent-a-gallon statewide gas tax hike that took effect last November. range.

The April inflation index marked the first time the BLS has released this data for Los Angeles and Orange counties. Previously, the agency included Riverside and San Bernardino counties in the Los Angeles region for the inflation data; those two counties have now been broken out into their own separate database.

Economy, education, energy and transportation reporter Howard Fine can be reached at [email protected]. Follow him on Twitter @howardafine.