Your chart: “Monthly US Total Gasoline Retail Sales by Refiners” is very misleading.
Only a small portion of the Gasoline Retail Sales is by the Refineries. As your first chart and second chart together show, far more Gasoline is sold to Retail by Blenders, not Refiners. The Refineries mostly sell to the Blenders, not direct to retail.
If you want to see total gasoline sales in the US, the total data is found at:
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=MGFUPUS2&f=M
Thanks for the link! Great data. I notice that the downturn still shows, but in a much more realistic way. I wonder what triggered the odd chart I posted.