"After an increase in 2010 of 3.3 percent, energy-related carbon dioxide emissions declined in 2011 by 2.4 percent and were 526 million metric tons (9 percent) below the 2005 level. Energy-related carbon dioxide emissions have declined in the United States in four out of the last six years...In 2011, GDP grew by 1.8 percent, but emissions decreased by 2.4 percent (136 million metric tons). This indicates that the carbon intensity of the economy declined by about 4.2 percent.2 The 2011 decrease is only the fourth year since 1990 to experience a decline in carbon intensity of greater than 3.5 percent for the economy as a whole and only the sixth year since 1990 to experience an emissions decline. Since 1990, energy-related carbon dioxide emissions in the United States have grown much more slowly than GDP – in 2007 emissions were 19 percent greater than their 1990 level, but by 2011 were only about 9 percent above the 1990 level. GDP has increased by 66 percent over that same time period."