The average price of regular gasoline nationwide has dropped another 25 cents a gallon in the past two weeks, to $2.47, but it was a bigger drop in Illinois.  Industry analyst Trilby Lundberg said Sunday that prices will likely keep falling.  Lundberg says the average price of regular gasoline is the lowest it’s been in more than five years.  She says lower crude oil prices are driving prices down, along with an abundant oil supply and the rising value of the U.S. dollar.  The highest-priced gas in the Lower 48 states was found in Long Island, New York, at $2.82 a gallon.  The lowest was in Tulsa, Oklahoma, at $2.06 a gallon.  It was $2.48 per gallon of regular gas in Illinois, while it was $2.78 two weeks ago.  The average price for midgrade gas in the U.S. is $2.71. For premium it’s $2.87.