The overall housing units main heating methods measured in the thousands of units per utility.
U.S. Department of Energy: Short Term Outlook - http://www.eia.doe.gov/emeu/steo/pub/contents.html
The average expenditures discussed below provide a broad guide to changes from last winter, but fuel expenditures for individual households are highly dependent on local weather conditions, market size, the size and efficiency of individual homes and their heating equipment, and thermostat settings.
Department of Energy: Home Heating and Cooling Tips - http://www1.eere.energy.gov/consumer/tips/heating_cooling.html
Heating and cooling your home uses more energy and drains more energy dollars than any other system in your home. Typically, 45% of your utility bill goes for heating and cooling.