Year	constant 2011 PPP $ per kg of oil equivalent
2000	5.87498755552457
2001	5.52364512492491
2002	5.23383309193958
2003	5.24359016813924
2004	5.30151252974373
2005	5.69848456247801
2006	6.11595802518563
2007	6.38624639236929
2008	7.31296322270206
2009	7.68448736326712
2010	8.05708492564999
2011	8.06893428016523
2012	6.93978604898974
2013	6.84101357118622
2014	6.51092152593921