Year kt of CO2 equivalent 1970 30.0712 1971 28.8934 1972 30.3225 1973 31.7915 1974 32.4329 1975 34.1441 1976 34.0384 1977 35.8448 1978 37.4172 1979 38.9435 1980 40.1023 1981 41.4119 1982 41.9906 1983 43.1531 1984 43.8917 1985 44.5059 1986 45.2793 1987 46.2038 1988 47.3548 1989 45.8573 1990 46.4886 1991 47.6965 1992 48.9552 1993 50.2266 1994 51.4761 1995 52.6878 1996 53.8501 1997 55.0175 1998 56.0646 1999 57.189 2000 58.318 2001 59.4542 2002 60.6005 2003 61.6726 2004 62.7558 2005 63.8273 2006 64.911 2007 66.0797 2008 67.3484 2009 68.6719 2010 70.0865 2011 70.787365 2012 71.48823