Year	thousand metric tons of CO2 equivalent
1990	4.31
1991	4.4425
1992	4.3025
1993	4.2425
1994	4.1475
1995	3.9775
1996	3.7075
1997	3.67
1998	3.4925
1999	3.345
2000	2.96
2001	2.395
2002	2.575
2003	2.4975
2004	2.2425
2005	2.0525
2006	1.835
2007	1.985
2008	1.72
2009	1.485
2010	1.4325
2011	1.31
2012	1.2625
2013	1.35
2014	1.3625
2015	1.3375
2016	1.335
2017	1.3225
2018	1.335
2019	1.3175
2020	1.335