Year	kg per 2015 US$ of GDP
1990	0.40622810294349276
1991	0.4032261813508216
1992	0.3961363373246033
1993	0.3937353331990447
1994	0.3879249580710549
1995	0.3827734396393617
1996	0.38297880691944997
1997	0.37763368677702075
1998	0.3665881958835812
1999	0.35599208989536113
2000	0.3505227810092736
2001	0.34601539691277167
2002	0.33829749062420195
2003	0.3373891677278801
2004	0.32993866626934626
2005	0.3219669851946548
2006	0.3109037191071624
2007	0.30687351711532984
2008	0.2979527385083296
2009	0.2904001378076162
2010	0.2935554616590589
2011	0.28297584471574744
2012	0.2751572416483598
2013	0.2721223103936471
2014	0.2612710638716921
2015	0.2535456221093566
2016	0.24754985556013953
2017	0.2407599227227645
2018	0.2357552838002643
2019	0.2242622328307796
2020	0.21268332822888608