Year	kg per 2015 US$ of GDP
1990	0.4532093267272503
1991	0.5261467383587974
1992	0.40424605071285424
1993	0.4039698198153803
1994	0.40106277374159505
1995	0.4006218274300371
1996	0.32329133956150385
1997	0.3930911547499838
1998	0.360843054554031
1999	0.3089721493167454
2000	0.31262716755248776
2001	0.3371140637014897
2002	0.29878368885998424
2003	0.27275363846826506
2004	0.23683389436156518
2005	0.24622953413027907
2006	0.2496185631791142
2007	0.2575797067856449
2008	0.2399462528740767
2009	0.284385287578705
2010	0.28047982278999206
2011	0.30366739722031266
2012	0.23771447390644312
2013	0.22374929115299888
2014	0.22750243414045165
2015	0.3076033792526034
2016	0.2967918677567807
2017	0.29846750321726284
2018	0.28933349631115746
2019	0.3243659545304851
2020	0.3511753584954138