Year	constant 2011 PPP $ per kg of oil equivalent
1990	15.9343831375409
1991	15.6263610250489
1992	16.2314738801737
1993	15.9729092918593
1994	17.5031887154767
1995	15.941225541711
1996	17.6425868468145
1997	18.3215563382218
1998	18.9897667350583
1999	18.7918288882253
2000	20.3582241969915
2001	18.8518386687107
2002	19.5726011167044
2003	16.720056846844
2004	16.2931145969193
2005	16.2271628605958
2006	13.2071379436612
2007	14.6345155320318
2008	14.4383837657295
2009	13.5890707906729
2010	13.5674489431458
2011	10.5382189928699
2012	9.54438628661032
2013	9.62391154401113
2014	10.264556821099