Year	PPP $ per kg of oil equivalent
1990	5.689881291010661
1991	11.743871861248673
1992	6.698565479976158
1993	6.591193445865163
1994	6.222610703530165
1995	6.498186440095457
1996	6.769215944888506
1997	6.985418407745346
1998	6.409224046593911
1999	5.948055452981255
2000	6.130661952624245
2001	5.886187931242709
2002	5.987936287245041
2003	6.7199409404057295
2004	7.129378227819886
2005	7.231485148212528
2006	8.207855980361447
2007	8.730660312588116
2008	8.341780148470773
2009	7.129743389466996
2010	6.89877286854361
2011	7.646621629761784
2012	7.365570600666813
2013	7.712990244581781
2014	7.394419326928757