The national average U.S. retail price of diesel fuel increased to $1.814 from the previous average of $1.780, the Department of Energy reported Monday, Aug. 9.Once again, the highest average prices in the nation were found in California, where the average cost was $2.113. Among the higher average prices was the West Coast region, at $2.030; the Central Atlantic region, at $1.891; the New England region, at $1.889; and the Rocky Mountain region, at $1.849.Other prices included the East Coast region, where the average price was $1.803; the Midwest region, at $1.781; the Lower Atlantic region, at $1.758; and in the Gulf Coast region, where the price was $1.756.Meanwhile, oil prices reached record highs in early August as fears persisted over tight international supply. U.S. light crude increased $1.02 cents to $44.97 a barrel, the highest price since the New York Mercantile Exchange launched oil futures in 1983.Oil prices have increased more than 30 percent this year as rapid demand growth, especially in the United States and China, has left little leeway for any supply disruptions, Reuters reported. Consumption is accelerating at its fastest pace in more than two decades.The Organization of Petroleum Exporting Countries (OPEC), which controls about half of the world’s crude exports, is pumping at the highest levels since 1979 as it tries to stem oil’s seemingly relentless price climb.OPEC output is running at 30 million barrels daily. Purnomo Yusgiantoro, the president of the oil cartel, has said that the group was ready to boost production by 1 to 1.5 million barrels a day if deemed necessary when oil ministers meet in Vienna Sept. 15 to review output policy.