Year thousand metric tons of CO2 equivalent 1990 43.508 1991 43.359 1992 42.2862 1993 40.9154 1994 41.8988 1995 46.0708 1996 47.2032 1997 45.8622 1998 44.1636 1999 42.9716 2000 41.571 2001 38.4122 2002 29.4722 2003 29.7702 2004 44.3722 2005 34.3594 2006 33.4058 2007 32.8396 2008 35.6408 2009 29.4126 2010 30.0086 2011 32.1542 2012 34.8958 2013 35.4322 2014 31.9158 2015 31.3794 2016 33.1674 2017 35.76 2018 31.4092 2019 31.0814 2020 31.3794