Year thousand metric tons of CO2 equivalent 1990 524.6125 1991 529.255 1992 498.335 1993 495.715 1994 493.395 1995 539.94 1996 523.27 1997 518.9525 1998 513.6925 1999 535.7325 2000 507.06 2001 460.6175 2002 458.52 2003 457.1025 2004 459.3825 2005 526.205 2006 509.8775 2007 517.73 2008 446.6875 2009 479.47 2010 478.8175 2011 472.8325 2012 464.98 2013 470.375 2014 436.2675 2015 420.365 2016 423.08 2017 423.4225 2018 401.53 2019 398.05 2020 373.865