Year thousand metric tons of CO2 equivalent 1990 23.3075 1991 23.3025 1992 23.3 1993 23.295 1994 23.225 1995 23.1725 1996 23.1025 1997 23.1 1998 23.1225 1999 23.1225 2000 19.57 2001 19.6075 2002 20.0525 2003 20.0425 2004 20.4225 2005 20.45 2006 20.3625 2007 20.61 2008 20.7475 2009 20.9625 2010 20.8425 2011 20.84 2012 20.8725 2013 20.9025 2014 21.4775 2015 21.4 2016 21.1225 2017 21.095 2018 21.0425 2019 20.7975 2020 20.5725