Year	constant 2011 PPP $ per kg of oil equivalent
1995	2.45683063277516
1996	2.69060852587227
1997	2.86511329423224
1998	2.90060702862001
1999	3.21456108980266
2000	3.54723678266995
2001	3.55505741954007
2002	3.77843845047856
2003	3.71079402006203
2004	3.96568635860241
2005	4.11633030415663
2006	4.37243567759642
2007	4.62850018123298
2008	5.00803215278823
2009	4.95619974768266
2010	4.80831710013493
2011	5.16949901993201
2012	5.19399143420245
2013	6.30147708717664
2014	6.15217978893095