This figure shows emissions of CO2 by fuel source across all sectors of the economy. The fuels shown are coal, natural gas, petroleum, as well as the total emissions. Emissions have declined since 2007 mostly due to the global recession. (Friedlingstein, 2010)
[1]
Source: EIA (2011)
Links:
[1] http://www.pewclimate.org/docUploads/facts-figures-us-emissions-co2-trends.jpg