Year	PPP $ per kg of oil equivalent
1990	0.6545875663833705
1991	0.7133842428707438
1992	0.6658709138764483
1993	0.7417028407362265
1994	0.7979245272939232
1995	0.8142401716451799
1996	0.9010229397710614
1997	0.9952449607769872
1998	1.0998659990808386
1999	1.2231204899657406
2000	1.1929442683577254
2001	1.3083535530911785
2002	1.4383656599529837
2003	1.4912321853020785
2004	1.5952129232465684
2005	1.7255716412623041
2006	1.8983788670418957
2007	2.0125052975289472
2008	2.1506592043367423
2009	2.2105910023391617
2010	2.3096817432693415
2011	2.427881575440556
2012	2.480908208253653
2013	2.552372907931164
2014	2.5837925926218386