AAA Michigan said average gas prices statewide are down about 8 cents in the past week to about $2.85 per gallon. The Dearborn-based auto club said the average price for self-serve regular unleaded gasoline is about 23 cents more than at the same point last year. Michigan’s lowest average price was about $2.75 per gallon in the Flint area. The highest was in the Ann Arbor area at about $2.93 a gallon. The Detroit-area’s average was about $2.90 per gallon, down about 3 cents. AAA Michigan surveys daily fuel prices at 2,800 gas stations across the state.