evidence: "As of this morning, there are 24 states with prices under $2 a gallon. But Missouri is lowest," said Patrick DeHaan, GasBuddy's senior petroleum analyst. [...] Thirteen states, many in the South, have gas taxes of less than 40 cents a gallon, according to the American Petroleum Institute. Seventeen states' gas taxes are more than 50 cents a gallon. [...] Regular unleaded gas prices peaked this year in late June at about $3.70 a gallon nationwide, according to the U.S. Energy Information Administration. This week the nationwide average is $2.55.