Year	PPP $ per kg of oil equivalent
1990	6.295776052144561
1991	6.126260386538623
1992	5.888592423261336
1993	5.478185422897033
1994	5.116884125547383
1995	6.5627240319269635
1996	6.879993309615579
1997	6.752161478030664
1998	7.388897841608749
1999	8.708193308642048
2000	9.446355742752461
2001	8.377384624213999
2002	8.899208620229432
2003	7.846283548709989
2004	7.378424562904185
2005	11.634114973199946
2006	12.168639338066685
2007	14.710707233851954
2008	13.296730177777198
2009	15.55106662406322
2010	15.0601685096541
2011	15.792006021266829
2012	16.762390303685926
2013	17.02487812329834
2014	16.508878388296544