Year	kg per 2015 US$ of GDP
1990	0.4211679318415601
1991	0.41540493906978426
1992	0.40548127754487295
1993	0.40043542113098657
1994	0.3905052616648382
1995	0.384653879259215
1996	0.3825642369202787
1997	0.3769969012088923
1998	0.36606472696652836
1999	0.3556895884013237
2000	0.34971249892707007
2001	0.3454815452500364
2002	0.3373910476275869
2003	0.3364205021316132
2004	0.3282116750788654
2005	0.31940637531628147
2006	0.30752822296675114
2007	0.30306383701597783
2008	0.29367115770211116
2009	0.28432902621529665
2010	0.2877138809622887
2011	0.27708469579824246
2012	0.2687704095130328
2013	0.2663959114002062
2014	0.25528020045670724
2015	0.24657965988247213
2016	0.2398673642102482
2017	0.23202816269575727
2018	0.22841466715344141
2019	0.21684087985091482
2020	0.20556507577558142