Year	PPP $ per kg of oil equivalent
1990	2.2342857456347853
1991	2.2226392520206395
1992	2.406784586270505
1993	2.633419568401828
1994	2.6736011101011017
1995	2.7876792308222984
1996	3.016305961134814
1997	3.285931118514331
1998	2.9029232945764023
1999	2.987968756029488
2000	3.237060737369321
2001	3.4162509195458513
2002	3.4724637559643026
2003	3.5563109811289446
2004	3.909336906430696
2005	4.338642764095528
2006	4.764936421361867
2007	5.146053317916053
2008	5.5569382382493515
2009	5.954657871507038
2010	6.034224315014837
2011	6.4068753644755665
2012	6.8250956604584
2013	7.621384408267506
2014	8.463102704085623