Year	PPP $ per kg of oil equivalent
1990	7.663374365527837
1991	7.861135269581029
1992	8.109118094463838
1993	9.079561736775723
1994	9.034328202610936
1995	8.053986987332715
1996	7.9215476444339386
1997	8.09797217210258
1998	8.230042120153408
1999	8.836678490952323
2000	8.24515198293999
2001	8.278980072461163
2002	9.039916676918388
2003	9.345312540879004
2004	10.61583895656769
2005	11.058318731283341
2006	11.841509901340302
2007	10.955064560134932
2008	12.916502608355964
2009	11.029706956353468
2010	11.48919125324788
2011	12.012777435667546
2012	12.965544738820105
2013	13.46868335687584
2014	13.383435029196184