Year	PPP $ per kg of oil equivalent
1990	2.045461775170913
1991	1.879789530552072
1992	2.341539096346364
1993	2.430733211561406
1994	2.511586689163899
1995	2.468212999055893
1996	2.4456827465246747
1997	2.838252918266921
1998	2.947866725815754
1999	3.461013349484611
2000	4.1454881219181
2001	3.958004866663091
2002	4.071195655702743
2003	4.454514027016491
2004	4.688705998550045
2005	5.449373884782131
2006	6.1829587041192084
2007	6.524527323353285
2008	6.962954333800629
2009	6.538190040064448
2010	8.829289522986008
2011	9.486034675855388
2012	10.005569963571816
2013	11.338873776622568
2014	11.80604622723791