Year	PPP $ per kg of oil equivalent
1990	8.081071641750855
1991	7.327077426449262
1992	8.1364940326741
1993	8.019518750523144
1994	7.901957002146771
1995	8.100110684584362
1996	8.265371934441044
1997	8.611268596387582
1998	8.540323938593726
1999	8.728246745482078
2000	10.12064717828518
2001	8.22773942761142
2002	8.629051198108744
2003	9.731125957154221
2004	10.262869022846141
2005	10.438778566143688
2006	11.384348509879258
2007	11.116534994416293
2008	9.883128957580123
2009	9.323028256205935
2010	9.31764089136739
2011	9.685590671510875
2012	9.43948338657367
2013	9.40501646245446
2014	9.749061521268251