Year	kg per 2011 PPP $ of GDP
1990	0.66630068343623
1991	0.646148053012427
1992	0.627302830193598
1993	0.624227475773594
1994	0.603532729202233
1995	0.595810729160326
1996	0.573916905123557
1997	0.563928389440455
1998	0.565737280651643
1999	0.569923536684346
2000	0.556372050801315
2001	0.544684743802645
2002	0.549219991121149
2003	0.53233982907211
2004	0.537387083720346
2005	0.527064941540748
2006	0.512122012652842
2007	0.497298580186339
2008	0.477423157659826
2009	0.4874994996576
2010	0.471747367499076
2011	0.451951544106216
2012	0.439785223427638
2013	0.437089556657695
2014	0.429602996824659