Year	PPP $ per kg of oil equivalent
1990	2.5871207802321114
1991	2.446422291396785
1992	2.1992294927523837
1993	1.9098981376362216
1994	1.8678569729285257
1995	1.8422579292705599
1996	1.795761250290669
1997	1.694337839968314
1998	1.6452701571488904
1999	1.5907848761118466
2000	1.5128476896635885
2001	1.4652254574302293
2002	1.480419837035795
2003	1.5365504548993998
2004	1.6196239332130928
2005	1.706862520227684
2006	1.785495128719832
2007	1.880227770809625
2008	1.9632858535645734
2009	1.9725982640685642
2010	2.0625640088327706
2011	2.118466444948779
2012	1.7707901749681447
2013	1.9645224274703776
2014	2.1964810701448587