Year	constant 2011 PPP $ per kg of oil equivalent
1990	11.6606270820368
1991	11.9122498138353
1992	12.1268555368262
1993	12.3062686978018
1994	11.8731694860367
1995	11.6939349266589
1996	11.5525346191212
1997	11.8124818095396
1998	11.8593932139658
1999	11.6681506836797
2000	11.5412513863374
2001	11.7367800221007
2002	11.8207725722972
2003	11.8978396408186
2004	12.5851615677749
2005	13.1512053389752
2006	12.7342317421422
2007	12.4588812126276
2008	12.7283092529785
2009	12.2436404551143
2010	12.178496101493
2011	12.7155913038708
2012	12.7930019676936
2013	14.0318874748799
2014	14.1979231826203
2015	14.1166306386271