Year thousand metric tons of CO2 equivalent 1990 44.8175 1991 46.3975 1992 46.8475 1993 47.31 1994 46.5675 1995 46.725 1996 46.595 1997 46.21 1998 45.0125 1999 46.7625 2000 48.2675 2001 45.9375 2002 46.21 2003 47.21 2004 49.2675 2005 50.64 2006 51.3175 2007 51.995 2008 53.1725 2009 53.3625 2010 53.6875 2011 53.405 2012 54.3275 2013 55.255 2014 55.9825 2015 56.3375 2016 56.1925 2017 56.2975 2018 56.475 2019 56.59 2020 56.775