The trend of gas prices and crude oil prices

I stumbled upon a site vancouver gas prices. Just for fun I looked at the comparison chart of crude oil price and gas price in Saskatoon. The trend was extremely disappointing. The gas prices constantly increased when the crude oil prices increased. But when the crude oil prices dipped the gas prices did not dip. In fact in one case the crude oil price dipped but the gas price increased. This is really disappointing. Something or somebody, somewhere in the system is not completely honest. I wonder, what is the government doing about it? You can find the chart in the page below.