Year	thousand metric tons of CO2 equivalent
1990	31.886
1991	31.9754
1992	33.8528
1993	33.674
1994	32.929
1995	33.4058
1996	30.9324
1997	31.886
1998	33.0482
1999	30.3662
2000	31.4688
2001	32.3926
2002	30.694
2003	31.2304
2004	29.3828
2005	31.1112
2006	31.6178
2007	30.843
2008	30.4258
2009	27.2372
2010	26.7008
2011	23.989
2012	24.734
2013	24.7042
2014	24.7638
2015	24.6744
2016	23.9294
2017	23.3334
2018	22.7374
2019	22.5586
2020	23.244