AAA Michigan says gasoline prices are down 15.6 cents per gallon over the past week to a statewide average of $2.49.

The auto club said Monday the statewide average is $1.68 per gallon lower than last year at this time.

Of the cities it surveys, AAA Michigan says the cheapest price for self-serve regular fuel is in the Detroit area, where it's $2.44 a gallon.

The highest average can be found in the Marquette area at $2.72.

The statewide average for biodiesel is $2.57 and $2.22 for ethanol.

Dearborn-based AAA Michigan surveys 2,800 Michigan gas stations daily.