Year	kg per 2015 US$ of GDP
1990	0.32353209767881763
1991	0.32624319301058224
1992	0.3244392050380576
1993	0.3196842472736096
1994	0.3201234586918829
1995	0.3236487173409555
1996	0.3312162112923436
1997	0.33411406012856
1998	0.33964405816307375
1999	0.33593263150078456
2000	0.3368853371811927
2001	0.3365073888879393
2002	0.3350728644823637
2003	0.33398535857936035
2004	0.3311955145155823
2005	0.32800313044251184
2006	0.3217585433949546
2007	0.3169197817565578
2008	0.31300562930302106
2009	0.3106468454084827
2010	0.31159556832684354
2011	0.31188907984278635
2012	0.3156291505677175
2013	0.3161074202624706
2014	0.31580342618358703
2015	0.3151200718521664
2016	0.31031784803179024
2017	0.3013671597636522
2018	0.28776721272915556
2019	0.2862050842918523
2020	0.2762958173346948