Year	kg per 2010 US$ of GDP
1997	0.728339800633996
1998	0.684329627900308
1999	0.666372991224722
2000	0.671398250030704
2001	0.688817943443485
2002	0.673880102255155
2003	0.684626793965639
2004	0.64951520887965
2005	0.66579816812088
2006	0.661001645811714
2007	0.656256255843274
2008	0.632200093886974
2009	0.612411934828248
2010	0.607984973131268
2011	0.593079986561661
2012	0.594908482080286
2013	0.573893103772806
2014	0.618002981437629