Year	kg per 2015 US$ of GDP
1990	0.5905004413169902
1991	0.5874633685269456
1992	0.574480828266712
1993	0.5679914588013338
1994	0.5534226096220076
1995	0.5522749185073264
1996	0.5446865891416781
1997	0.5338382717212203
1998	0.5226701668983728
1999	0.5083145385689948
2000	0.5017771428097672
2001	0.49919235648442645
2002	0.49478795981192625
2003	0.5018581200083874
2004	0.5024180315380464
2005	0.5014474866849022
2006	0.49596224403703965
2007	0.4931912496337199
2008	0.48661323539062856
2009	0.4869523622369976
2010	0.4944732746334
2011	0.4932204740441442
2012	0.4857326962645069
2013	0.48150046415259284
2014	0.46885067997928453
2015	0.45210100613027365
2016	0.4406731052910499
2017	0.4326979875283923
2018	0.42946933368517987
2019	0.4174336822021813
2020	0.4068804581224095