Year thousand metric tons of CO2 equivalent 1970 1.8261976 1971 1.8269478 1972 1.8448131 1973 1.8220901 1974 1.821157 1975 1.8296076 1976 2.6258457 1977 2.7775194 1978 5.303201 1979 6.067785 1980 6.170271 1981 7.047013 1982 7.624574 1983 7.290487 1984 7.828492 1985 8.650364 1986 6.47466 1987 8.943996 1988 11.000443 1989 11.871481 1990 11.823462 1991 11.862274 1992 12.133462 1993 12.684115 1994 13.239976 1995 13.292831 1996 8.335714 1997 38.4276 1998 6.535978 1999 5.815693 2000 5.468121 2001 5.173776 2002 5.335968 2003 5.007275 2004 5.0127 2005 5.168971 2006 5.765411 2007 5.727219 2008 5.884513 2009 6.123027 2010 6.361541 2011 6.42515641 2012 6.48877182