Massachusetts gas prices drop another 2 cents By Ira Kantor/ BostonHerald.com Monday, December 3, 2012 Bay State gas prices are down another two cents this week, according to AAA Southern New England.            Self-serve, regular unleaded gas is currently averaging $3.54 a gallon, 16 cents above the national average of $3.38.            Local prices are down 11 cents over the past month. A year ago at this time, the Massachusetts average price was $3.28.            Midgrade unleaded and premium unleaded also dropped two cents a gallon this week to $3.74 and $3.86, respectively. Diesel remained unchanged at $4.08 a gallon.            The range in prices in the latest AAA survey for unleaded regular is 37 cents, from a low of $3.42 to a high of $3.79. ( -— ira.kantor@bostonherald.com )