Year	constant 2011 PPP $ per kg of oil equivalent
1990	14.4019135952485
1991	13.8804481719216
1992	11.7391114592441
1993	12.3200052651764
1994	13.0656787250379
1995	13.3317439064918
1996	13.4395886579183
1997	14.0095213946143
1998	15.0715181255466
1999	14.2063613027575
2000	13.4941797641869
2001	13.8822467812924
2002	13.6298067668854
2003	13.239271877983
2004	11.6599584486632
2005	12.1152952336343
2006	12.0075918080144
2007	12.049920670668
2008	12.3973479362546
2009	12.3441913927413
2010	12.7179016098325
2011	13.2403201339523
2012	13.6486712769704
2013	13.6395965969002
2014	13.9383400294665