Year	PPP $ per kg of oil equivalent
1990	1.7724286697989056
1991	1.7638198316832947
1992	1.8078411203938867
1993	1.8808338865314376
1994	1.961993557406546
1995	2.0389170893735193
1996	2.115268072479711
1997	2.2949434907764448
1998	2.2071838105830244
1999	2.2791423930985593
2000	2.494465948629752
2001	2.6250791418590484
2002	2.785213087596081
2003	2.9267057783613684
2004	3.2278450305148816
2005	3.5740714875681134
2006	4.084487278954675
2007	4.505248087124491
2008	5.075182715811226
2009	5.344595527187854
2010	5.372689210905412
2011	5.691983100536722
2012	5.988817305177176
2013	6.54426461613523
2014	6.948981097266392