Year	PPP $ per kg of oil equivalent
1990	1.170517007541911
1991	1.2271211157249071
1992	1.3597070365065798
1993	1.5101700440107175
1994	1.6038437544932411
1995	1.585952810179436
1996	1.6166969094942525
1997	1.8367195007713961
1998	2.0553299015931663
1999	2.213369088775138
2000	2.3564194640746368
2001	2.5126843111693633
2002	2.629313859416906
2003	2.787918707897155
2004	3.0852334073637806
2005	3.4845991237966545
2006	3.712018557979701
2007	4.227181928766623
2008	4.741468212597458
2009	5.034692489745081
2010	5.2940977465811745
2011	5.340502752833757
2012	5.610934592843423
2013	6.582764190374718
2014	6.482996157732357