Year	thousand metric tons of CO2 equivalent
1970	5.199382
1971	5.254407
1972	5.712556
1973	5.914676
1974	6.501785
1975	7.921523
1976	8.418608
1977	8.753408
1978	9.403819
1979	9.138397
1980	10.817822
1981	10.472854
1982	11.011386
1983	13.331736
1984	14.242237
1985	12.116381
1986	11.135355
1987	11.190442
1988	17.293722
1989	19.682985
1990	14.199147
1991	13.543404
1992	11.705073
1993	11.718558
1994	12.137616
1995	12.023815
1996	11.885338
1997	11.574873
1998	14.864686
1999	15.101495
2000	14.357247
2001	13.924983
2002	13.956386
2003	14.106395
2004	15.512214
2005	16.171057
2006	16.848097
2007	17.263125
2008	18.291395
2009	19.260052
2010	20.449026
2011	20.65351626
2012	20.85800652