Year thousand metric tons of CO2 equivalent 1990 3.6025 1991 3.5325 1992 3.5375 1993 3.5425 1994 3.5425 1995 3.5425 1996 3.7375 1997 3.7375 1998 3.7375 1999 3.7375 2000 4.1475 2001 4.2775 2002 4.755 2003 4.755 2004 4.835 2005 4.915 2006 4.955 2007 5.0175 2008 5.0325 2009 5.0425 2010 5.1975 2011 5.2075 2012 5.3975 2013 5.4025 2014 5.59 2015 5.6625 2016 5.735 2017 5.7775 2018 5.8075 2019 5.7775 2020 5.8325