Press release: “…Total emissions of the six main greenhouse gases in 2005 were equivalent to 7,260 million metric tons of carbon dioxide. These gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. The report indicates that overall emissions have grown by 16 percent from 1990 to 2005, while the U.S. economy has grown by 55 percent over the same period.”