Year	PPP $ per kg of oil equivalent
1992	2.092430937965379
1993	2.3148303114610145
1994	2.778441736212661
1995	2.778521944982822
1996	2.9450148533074456
1997	3.2532585647989647
1998	5.150197102063792
1999	5.03807986524046
2000	4.945104856480678
2001	5.24830751320145
2002	5.440925550858536
2003	5.043450646355808
2004	5.663495359822756
2005	5.8468581472213375
2006	6.551749670176971
2007	6.608686960373206
2008	6.459565002330139
2009	6.308441519105909
2010	6.357851040460934
2011	6.8777127924025105