The Oil Price Information Service collects wholesale heating oil prices each week for twenty–six (26) states in the Midwest Region and East Coast Region during the heating season (October to March). The Energy Information Administration, the independent statistical and analytical agency within the U.S. Department of Energy, uses the prices collected by the Oil Price Information Service to calculate a state average price, a regional average price, and a national average price which can be seen in the report Weekly Heating Oil and Propane Prices.
Prices are not collected during the off season (April through September).
For statistical purposes, the Energy Information Administration defines the Midwest Region to include the states of Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, and Wisconsin. All but two states are being surveyed. Those two states are Oklahoma and Tennessee.