Year	constant 2011 PPP $ per kg of oil equivalent
2000	5.09166170227471
2001	5.25126413361174
2002	5.23679969199654
2003	5.27160484167514
2004	5.37909352228921
2005	5.87652691873065
2006	6.07725481848654
2007	6.26988378668225
2008	5.94019244620369
2009	5.58629806527026
2010	5.63095298401537
2011	5.82479670688993
2012	6.39818929175271
2013	6.64716332352995
2014	7.17472999889813