Year	kg per PPP $ of GDP
1990	0.5574860832277679
1991	0.5244091201961412
1992	0.5250023844562027
1993	0.5206114402588777
1994	0.510226132536473
1995	0.508523268296914
1996	0.48317318690497324
1997	0.45803947740686834
1998	0.4506650520952974
1999	0.43981016278142654
2000	0.44786088683791675
2001	0.4243120350614984
2002	0.391776542323025
2003	0.38373895504920846
2004	0.3579546275600077
2005	0.3627652592427255
2006	0.3200773813635639
2007	0.32192656889367427
2008	0.2937399494484058
2009	0.28097016534475094
2010	0.2821675231723256
2011	0.2965740164699098
2012	0.2910672928925667
2013	0.2543759534941277
2014	0.2398138669910899
2015	0.23486556418975155
2016	0.22548459719366223
2017	0.2171250402557342
2018	0.2045453070377231
2019	0.17700316113314452
2020	0.16388719881093042