Year	PPP $ per kg of oil equivalent
1990	1.966591555886825
1991	2.1470961901280803
1992	2.1977954791499172
1993	2.3436183133161257
1994	2.6375536117597718
1995	2.6414505921913554
1996	2.7223460630728002
1997	2.7955205372281497
1998	3.0405361505501785
1999	3.4679334644947413
2000	3.6233488765540627
2001	3.919270582231665
2002	4.159953781306791
2003	4.126204943248322
2004	4.9850920166552095
2005	5.304009243273632
2006	6.132245308938599
2007	7.196574431843979
2008	8.69986207319909
2009	9.711432073653473
2010	10.029737154580033
2011	10.579996790680863
2012	11.372770400711554
2013	12.328465713149406
2014	12.961674320005935