Gas prices in Mississippi have jumped an average of 11 cents in the past week, now at their highest level since early February. AAA says the statewide average price has been climbing for the last nine days, now at around $3.14. The auto club says higher oil prices and a strong demand for gas have been driving up pump prices. But GasBuddy.com says, despite the increases, gas is still selling for less than $3 a gallon in some locations, including Carthage.