The average price of gasoline has decreased over the past week from $2.27 a gallon for regular grade to $2.20. It was $2.65 per gallon one year ago. For Illinois, the price is relatively unchanged for the past 2 weeks, going up to $2.29 from $2.28 per gallon of regular gas. The price of regular gas in Nashville remained unchanged at $2.18 per gallon for the 2nd week in a row.