Hawaii historically has the highest electricity and gas prices in the nation.

But steep drops in both of those categories left Honolulu’s inflation barely discernible during the first half of 2015 and on track to finish at its lowest level since 2009.

The consumer price index — the most widely used measure of inflation — rose a scant 0.7 percent from the same six-month period a year ago and slid 0.5 percent from the second half of 2014, according to data released prematurely by the U.S. Bureau of Labor Statistics.

Typically, the six-month data for Honolulu and other select metropolitan areas are released in February and August, but program upgrades by the national office resulted in the figures being released late last month on the BLS website, according to BLS regional economist Matt Insco. The West Region office plans to officially release the information on Wednesday.

The low six-month CPI number for Honolulu came as a surprise to Eugene Tian, chief economist for the state Department of Business, Economic Development & Tourism. DBEDT had forecast in February that inflation would rise 1.5 percent this year, slightly above the 1.4 percent it increased in 2014.

Nationally, the consumer price index actually slipped 0.1 percent during the first half of the year compared with the year-earlier period.

“We didn’t expect the energy prices would impact the overall consumer price index (in Honolulu) by that much,” Tian said Wednesday. “But we expect inflation in the second half will increase more because energy prices have been declining for a while and during the second half of last year energy prices already were low. The main reason inflation is low is because of the oil price.”

Gas prices, including all grades, plummeted 26.2 percent during the first half of 2015 compared with the year-earlier period, according to CPI data. Natural gas costs decreased 20.5 percent while electricity prices fell 18.7 percent.

Honolulu gas prices are now more than $1 below where they were a year ago and as of Wednesday were at an average of $3.07 per gallon for regular, down from $4.29 a year earlier, according to motor club and travel organization AAA.

Rates for Hawaiian Electric Co. customers on Oahu have been dropping and were 26.4 cents a kilowatt­-hour in August, a drop of 24.4 percent from 34.9 cents a kilowatt-hour in the year-earlier period, according to the utility. HECO uses low-sulfur fuel oil, which has seen a significant drop in price this year, to generate most of the electricity consumed on Oahu.

Tian said consumers are benefiting from the low inflation.

“This is good for the consumer because they will feel the purchasing power of their money is stronger,” he said.

Tian said personal income growth before being adjusted for inflation is 4 percent and that the 0.7 percent inflation number represents real, or inflation-adjusted, income growth of 3.3 percent.

“Compared with a 1.7 percent increase in real income growth of the last 20 years, this is good growth,” he said.

Tian said DBEDT will lower its full-year inflation projection to between 1 percent and 1.5 percent when its quarterly economic forecast is released next week. He said DBEDT still is working on its forecasts for inflation and other economic indicators.

The last time Honolulu inflation was below 0.7 percent during a six-month period was in the first half of 2009 when it was 0.3 percent. It finished the year up 0.5 percent after rising 0.7 percent during the second half of the year.

The University of Hawaii Economic Research Organization forecast in February that Honolulu inflation would rise 0.7 percent this year.

Despite the low inflation so far this year, film director David Rosen of Kailua said he doesn’t think the economic indicators are portraying a true picture of what is happening in the economy.

“Even though those (electricity and gas prices) are down (in recent months), it seems like everything else is up,” Rosen said. “Groceries are up, the cost of labor is up if you need to hire anybody to work on your house or a contract on a job. So it seems that the true cost of inflation might be actually higher than the indicators would say.”

Food and beverages, for example, were up 4.2 percent during the first six months from the year-earlier period.

And core inflation, which excludes the volatile food and energy sectors, was up 2.3 percent during the first half of the year. One of the biggest gainers was medical care, which jumped 4.8 percent. The category that combines education and communication increased 3.1 percent.

Housing, a major part of the consumer price index, rose just 1 percent, though. The component is made up of the rent paid for a primary residence and the homeowner’s equivalent of renting a primary residence, which includes household furniture and appliances.

Roger Styan, a retired agricultural research employee who rents a room in Lanikai, said his monthly housing payment has been stable and that he doesn’t have to worry about utility costs because they are included in the rent. But Styan noted that his fixed personal expenses probably have gone up 3 percent during the past year.

“My auto insurance increased about $10 a month this year and my Hawaii Dental Service premium went up about $2 or $3 a month,” he said. “Those are pretty small increases.”

Still, Styan noted that inflation in Honolulu also can be a reflection of where someone lives.

“My rent has been very stable, but I know from looking at the market on rentals over the last two or three years that rental prices on the windward side have gone up 3 to 5 percent a year,” he said.