Year	PPP $ per kg of oil equivalent
1990	1.4921048428091201
1991	1.566216904832591
1992	1.881423380466424
1993	2.0948357320694466
1994	2.3683011482810374
1995	2.680146387819252
1996	2.527159505129042
1997	3.004264745088419
1998	2.91416413652565
1999	3.505789136168483
2000	3.933106674544031
2001	4.556685772871211
2002	4.117630890959002
2003	4.221398841565404
2004	4.706937257799542
2005	4.785171912548751
2006	5.1674449796827195
2007	4.940772753511277
2008	5.104013305964667
2009	5.786654560641865
2010	6.106881552719516
2011	5.492999997636488
2012	4.906770823577627
2013	5.8541456147769155
2014	6.5792694928971