Year	kg per 2015 US$ of GDP
1990	1.055333933486877
1991	1.0226423912973708
1992	0.9382718010099684
1993	0.8814186559762016
1994	0.8513005605051697
1995	0.7988404390514899
1996	0.7288329860512545
1997	0.6826501194022312
1998	0.6504697904467853
1999	0.6661315564079171
2000	0.6765170393263593
2001	0.6714873472393436
2002	0.6358893704930826
2003	0.6339544632366036
2004	0.6182045542702387
2005	0.6404796671379402
2006	0.6332777591380909
2007	0.5834516532279621
2008	0.5912170029399394
2009	0.5276645708534874
2010	0.4932258919932555
2011	0.45364142562692794
2012	0.43870417473913215
2013	0.3870123987967918
2014	0.3835194174968053
2015	0.3476226991622721
2016	0.3514638653850213
2017	0.4092398470616638
2018	0.4047900756793652
2019	0.4054736849411316
2020	0.37971324879963003