I don’t think I can prove it, but inflation seems to correlate with election years. Increases in fuel prices push other prices up. Retail gasoline prices are set by the refiners, not the dealers. That is why there is so little variation between stations. If Republicans are in, power retail gasoline prices go down which makes people feel good and might encourage re-election. If Democrats are in power the retail gasoline prices go up. This makes people angry and might help the opposition. It’s something for someone with more sophisticated statistics to analyze. Republicans have been kind to oil.