Year	thousand metric tons of CO2 equivalent
1990	4.3175
1991	4.4275
1992	4.55
1993	4.5375
1994	4.615
1995	4.6875
1996	4.775
1997	4.83
1998	4.8225
1999	4.89
2000	5.05
2001	5.19
2002	5.4875
2003	5.7525
2004	5.125
2005	4.8325
2006	4.38
2007	4.3925
2008	4.1525
2009	4.2075
2010	3.9125
2011	3.7475
2012	3.9175
2013	4.1825
2014	4.3375
2015	4.275
2016	4.525
2017	4.7925
2018	4.7175
2019	4.6925
2020	4.97