Year thousand metric tons of CO2 equivalent 1990 5888 1991 6565 1992 6353.9 1993 6226.2 1994 5745.2 1995 5819.6 1996 6107.8 1997 5596.9 1998 5611.9 1999 5485.2 2000 5352.4 2001 5485.3 2002 5254.4 2003 5479.4 2004 5490.5 2005 5394.1 2006 5077 2007 4952.1 2008 5140.3 2009 5126.3 2010 5537 2011 4658.2 2012 5012.1 2013 5282.2 2014 4487.6 2015 4722.2 2016 5021.3 2017 4916.5 2018 4776.2 2019 4843.2 2020 4541.2