Year	PPP $ per kg of oil equivalent
1990	6.835561635501659
1991	8.05635511469515
1992	8.056977086641288
1993	7.647611307505318
1994	7.051476546653971
1995	6.64898500034517
1996	6.50999672517933
1997	6.854226601984268
1998	6.604918718827248
1999	6.839054707298227
2000	6.910281061457467
2001	6.737179956536023
2002	6.51573472698493
2003	7.298432513809895
2004	7.615646730303909
2005	8.868425879118211
2006	9.629868031727995
2007	11.29994526521448
2008	10.794693349747853
2009	9.576149519586076
2010	9.452267632308692
2011	7.275243998941966
2012	9.610694493000853
2013	6.868361230650314
2014	6.298051955312653