Illinois Gas Prices Up 7.5 Cents Per Gallon From A Week Ago Illinois, May 20- Average retail gasoline prices in Illinois have risen 7.5 cents per gallon in the past week, averaging $4.07/g yesterday, according to GasBuddy's daily survey of 4,378 gas outlets in Illinois. This compares with the national average that has increased 8.9 cents per gallon in the last week to $3.67/g, according to gasoline price website GasBuddy.com. Including the change in gas prices in Illinois during the past week, prices yesterday were 20.5 cents per gallon higher than the same day one year ago and are 28.9 cents per gallon higher than a month ago. The national average has increased 16.6 cents per gallon during the last month and stands 3.0 cents per gallon lower than this day one year ago. "The last seven days have delivered some shocks at the pump for motorists in the nation's Midwest," said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan. "I don't believe I've ever seen gasoline prices in the Midwest surpass California- areas of Nebraska, Minnesota, Oklahoma, North and South Dakota, and Kansas- have done that. Gas price records in these areas aren't being quietly replaced, they're being blown out of the water. I don't believe I've ever seen such crazy trends in gasoline prices occur all at one- prices spiking in one area, falling in another, and holding steady in others. What we're seeing today is certainly rare."