Year	PPP $ per kg of oil equivalent
1991	2.999886735825764
1992	2.7381176444457243
1993	2.805830491565088
1994	2.6267831762441864
1995	2.8510452364731753
1996	3.21932116414856
1997	3.336830224313882
1998	6.378422670694362
1999	9.842298064062637
2000	9.998134991489906
2001	9.305560929960523
2002	9.12312175503961
2003	6.413145228843695
2004	9.815189284904493
2005	10.16401378890072
2006	11.73109927934784
2007	12.064454234148972
2008	12.286541288996055
2009	10.663435049168234
2010	10.085652325616751
2011	10.118409523085509
2012	10.56829195608502
2013	10.485696947920125
2014	9.72697627462474