Year	PPP $ per kg of oil equivalent
1990	0.8657386451800668
1991	0.8035843454050565
1992	0.7327609722468567
1993	0.8146418936663657
1994	0.826497882613319
1995	0.8635587634159301
1996	0.9560676815895129
1997	0.9751096408186656
1998	0.9236643769010611
1999	0.9582091324931543
2000	1.0081547393438046
2001	1.0759444024689613
2002	1.077229379477939
2003	1.0416202870560873
2004	1.1795267567628742
2005	1.327471756037903
2006	1.472110495480823
2007	1.6339711665727015
2008	1.7909496201287822
2009	1.907417861335291
2010	2.113425379192277
2011	2.319789437389108
2012	2.4898735525119537
2013	2.6272102318467305
2014	3.103356954829735