Year	kg per PPP $ of GDP
1990	1.5271801574046224
1991	1.420946122173741
1992	1.2716040910907835
1993	1.020042661262399
1994	0.7907534901579827
1995	0.7313326822266172
1996	0.7151749326234104
1997	0.6891123842836026
1998	0.6454286155222875
1999	0.5877140873108471
2000	0.5541410580989927
2001	0.5923968938906315
2002	0.5895126072945042
2003	0.6156364764232507
2004	0.5787004540880898
2005	0.5770131060860089
2006	0.5640438832656017
2007	0.5355138896373338
2008	0.4964055616860457
2009	0.4907060876701762
2010	0.5287124988294521
2011	0.5389380518933617
2012	0.5015225094842757
2013	0.5186126187937239
2014	0.5070832664593051
2015	0.5257617759669647
2016	0.4765687839003113
2017	0.46751180443342905
2018	0.4430710927553043
2019	0.42464123127294107
2020	0.4237067728436932