That graph and common knowledge shows a 1 to 1 correlation. Right now demand is down and production is up so prices are going down. It isn't going to follow exactly since the prices have to reach the pump first.
If you own a station and you know your going to have to pay more for the next truckload you are going to raise prices immediately. If you are going to have to pay less, you raise it later and enjoy the profit, unless your competition lowers his.
The libs have eliminated the competition by forcing the independents out with their clean-up laws which made owners pay millions to keep running. Now the independents are gone and enjoy the monopoly. Thank you libs.
So the overriding factor is the price of crude as the chart shows.
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Also during the Clinton years refineries were shut down, this does affect us when supplies are tight unlike now when there is plent of oil on the market. I still believe in what i said but you raise valid points