Year	kg per 2015 US$ of GDP
1990	0.7425614627035977
1991	0.7712548691219936
1992	0.7760875028934482
1993	0.7768461164655338
1994	0.734968995137295
1995	0.7309443440692749
1996	0.7438690946332246
1997	0.7339596869446543
1998	0.733306376614038
1999	0.7378573566353448
2000	0.7463518668922112
2001	0.7313216705472948
2002	0.672824939101218
2003	0.6448678858457132
2004	0.624037153234398
2005	0.587014759997789
2006	0.5694845714036489
2007	0.5418503116071015
2008	0.5280514347383647
2009	0.4799655090936297
2010	0.47916885281164484
2011	0.47052465782925845
2012	0.4356993796125613
2013	0.4300880901872263
2014	0.4185178050886876
2015	0.4034537983219404
2016	0.41962362078102866
2017	0.42723607732111435
2018	0.4104450834094661
2019	0.4066499762582506
2020	0.40073960103338674