Year	PPP $ per kg of oil equivalent
1990	8.695549414653708
1991	8.396666523423905
1992	8.540860472559952
1993	8.52928663317153
1994	8.956409285414587
1995	9.097108512778158
1996	9.959560242783525
1997	9.995638305921695
1998	10.265013143838042
1999	10.064232433211908
2000	10.51721561421207
2001	11.054141321605771
2002	11.061561031261451
2003	11.303792269754513
2004	11.981238465524443
2005	12.507046106038237
2006	12.3892346077736
2007	12.363120847945824
2008	12.765677933714324
2009	11.885554072395363
2010	12.820273899511799
2011	12.919459846395462
2012	11.827642396334308
2013	11.60251159409869
2014	11.1487443934191