Energy Information Administration – October 7, 2013

“Measuring current U.S. gasoline demand can be difficult, as there are 160,000 retail gasoline stations and more than 250 million vehicles in the country. EIA traditionally used average daily product supplied (the dark blue line in the accompanying graph), calculated from weekly and monthly data on refinery operations and changes in product inventories at refineries and terminals, as one estimate of daily gasoline consumption over a given week. However, issues surrounding the timing and availability of some data, notably the lack of weekly product export data, can sometimes skew the product supplied calculation. Another proxy for gasoline consumption is the amount of gasoline blended with ethanol each week. This measure (the green line in the graph above) is based on only one factor and represents nearly all gasoline consumed in a given time frame. In 2010, about 85% of gasoline consumed in the United States contained ethanol, almost all in a 10-percent blend often referred to as E10. The share of the gasoline pool that contains ethanol has continued to rise, and most of this fuel is E10.”