Year	constant 2011 PPP $ per kg of oil equivalent
1990	0.846785509569185
1991	0.892441341120105
1992	0.83510949545817
1993	0.890875652330078
1994	0.935888619867628
1995	0.93646062644091
1996	1.16610247455541
1997	1.25519191651974
1998	1.3902429447531
1999	1.4700126512417
2000	1.4146801042557
2001	1.51561669120839
2002	1.62764544071976
2003	1.64373031416833
2004	1.70607193634397
2005	1.82992551952331
2006	1.95189784233432
2007	2.01048045630678
2008	2.10784661109147
2009	2.16190282943238
2010	2.23184640784653
2011	2.29828651989063
2012	2.4184892021384
2013	2.50182423856647
2014	2.52532272938121