Year	thousand metric tons of CO2 equivalent
1970	12.813974
1971	12.555992
1972	12.863078
1973	13.173264
1974	13.282973
1975	14.039838
1976	15.220969
1977	17.400486
1978	17.148301
1979	17.419737
1980	20.323972
1981	24.381686
1982	27.310411
1983	30.652893
1984	36.96874
1985	32.87581
1986	38.22021
1987	37.78435
1988	39.20322
1989	37.65322
1990	36.77871
1991	36.47026
1992	38.12597
1993	37.80915
1994	33.99181
1995	33.8272
1996	33.95926
1997	34.19021
1998	35.40076
1999	35.76346
2000	39.11828
2001	32.83148
2002	37.55216
2003	39.80152
2004	39.18989
2005	39.57863
2006	38.97072
2007	39.2274
2008	39.43882
2009	36.70121
2010	36.67765
2011	37.0444265
2012	37.411203