The average price of a gallon of regular gasoline nationwide went down again in the past week. Gas went down from $2.36 per gallon to $2.30, while it was at $3.37 per gallon one year ago.  There was a significant decrease in Illinois for the past week again, as it went down from $2.54 per gallon of regular gas to $2.43.  It decreased significantly again in Nashville as well from $2.28 per gallon to $2.18.