[thackney]

What I am asking is why all of a sudden dramatic jump in the gasoline prices for no apparent reason?

Does this graph help? Changes in enviromental regulations including ethanol caused refineries to shut down to make adjustments to the process. This happens every spring but combined with ethanol replacing MTBE requirements was a disaster.

[danmar]

Well, based on your graph 05=06 on average. What I can not understand is the spike on monthly especially on weekly!
What factors have you employed to generate that graph?