The average national retail price of diesel declined from last week’s total of $1.871 to $1.869 per gallon his week, the U.S. Energy Department announced Sept. 7. The highest prices in the nation occurred in California, where the price currently averages $2.136 per gallon, and on rest of the West Coast, where the price stands at $2.038. Then comes New England, where the price is $1.949; the Central Atlantic, where the price is $1.933; and the Rocky Mountain states, where the price is $1.918. Other prices: $1.818 in the Lower Atlantic states, $1.845 in the Midwest and $1.819 in the Gulf Coast region.