If you've filled up lately in Tampa Bay, you might have noticed that gas prices keep falling. And falling. Tampa Bay gas averaged $2.03 a gallon Thursday, down six cents over the week according to AAA, the Auto Club Group, and prices as low as $1.99 a gallon were spotted in Tampa. Gas across the state was $2.15 a gallon on average, down 5 cents over the week."Falling gas prices continue to be 'the gift that keeps giving' this holiday season," said Mark Jenkins, AAA spokesman, in a release late last week. The primary driver for the drop, Jenkins said, is weakness in the stock market and general concerns about too much crude oil supply worldwide. Nationally, gas was $2.25 a gallon Thursday.Contact Malena Carollo at [email protected] or (727) 892-2249. Follow @malenacarollo.