Year	constant 2011 PPP $ per kg of oil equivalent
1990	10.7368443899511
1991	11.2723399123769
1992	11.2607730841103
1993	11.1678773791177
1994	11.1085656815965
1995	10.7330910065455
1996	11.1524752094927
1997	11.1551498393383
1998	11.2546240244771
1999	11.6259914687445
2000	11.8306675092094
2001	11.3644182411212
2002	11.524718742233
2003	11.4555004946623
2004	11.8366381695515
2005	12.144201407035
2006	12.0908050420847
2007	12.3897808364481
2008	12.5142792290076
2009	12.4952752286383
2010	12.1804026703379
2011	12.5000603104995
2012	12.6888969477277
2013	13.1722780799356
2014	13.3787606347948