Year	PPP $ per kg of oil equivalent
1990	2.627030297744332
1991	2.6409772040886135
1992	2.347177298583975
1993	2.56544934392593
1994	2.6886932335931593
1995	2.6884349439052166
1996	2.362028704347839
1997	2.4513992195683514
1998	2.4832592319215863
1999	2.6261253641658184
2000	3.030631051299443
2001	3.4403779217930897
2002	3.859217144076328
2003	4.286384690382519
2004	4.489343894917235
2005	4.949885775209555
2006	5.295075760878484
2007	5.485439142763359
2008	6.340119391112292
2009	7.627419646527756
2010	8.056948338904265
2011	8.806497226852617
2012	9.148866902458996
2013	9.219261967938465
2014	9.467897379462853