Year	kg per 2015 US$ of GDP
1990	0.5534184414992718
1991	0.5640151840821103
1992	0.5582300366988268
1993	0.5465423391884967
1994	0.5273389888564226
1995	0.5247271210418823
1996	0.5350860520747736
1997	0.5260460899984057
1998	0.5272601488205477
1999	0.5280140607908432
2000	0.5291240418479449
2001	0.5250398207170562
2002	0.5002104917137762
2003	0.488604632607248
2004	0.4778493988558437
2005	0.46522141979927173
2006	0.45468679539919277
2007	0.4428693933357186
2008	0.43154091488207336
2009	0.40620735716405615
2010	0.4046369794941576
2011	0.4025487555397014
2012	0.38628517353830605
2013	0.37609170060871916
2014	0.3709233534530432
2015	0.36487855608679365
2016	0.37982210814205347
2017	0.3888042578089097
2018	0.3830696145764698
2019	0.3776346282007054
2020	0.3672051863519193