Year	PPP $ per kg of oil equivalent
1990	11.247839025856381
1991	8.911589770774894
1992	10.573911637294511
1993	10.55824668498547
1994	11.004729143509845
1995	11.678474906317943
1996	11.92102805321682
1997	11.9553126322878
1998	12.321450588977607
1999	12.096553619846262
2000	12.26059700451711
2001	12.913094488834066
2002	12.334303906559047
2003	11.49025631965851
2004	11.671885069481608
2005	10.97016197152486
2006	7.649313370805203
2007	7.155086276800861
2008	8.921437247759892
2009	9.42682030432453
2010	8.200473977132736
2011	7.322735292430074
2012	7.49019377464701
2013	7.376713390469343
2014	7.277941221770812