Year	PPP $ per kg of oil equivalent
1990	1.6635052490956068
1991	1.723684301470686
1992	1.6839078754880896
1993	1.4792823974537712
1994	1.3368028276303165
1995	1.2811220827377405
1996	1.5636399057521784
1997	1.7467352631560231
1998	1.8717305249103675
1999	2.192154891017575
2000	2.409863841796692
2001	2.672829845385015
2002	2.941062912059789
2003	3.1424644580980843
2004	3.3526323029645857
2005	4.213354156308227
2006	5.927540213682038
2007	8.313345732149823
2008	8.532739553754991
2009	10.473006385614466
2010	11.473443303810194
2011	10.81138032711858
2012	10.858968689173572
2013	11.714702630743332
2014	11.692874987982043