Year	PPP $ per kg of oil equivalent
1990	8.368484047011695
1991	7.891636054911303
1992	7.863785580215104
1993	8.3880442068541
1994	9.523785249453606
1995	8.47887472729746
1996	8.823954651604888
1997	8.563308765874421
1998	8.647654063880593
1999	8.863828085512337
2000	9.273550825399612
2001	10.522581737441902
2002	11.35898864888901
2003	10.265826613216708
2004	11.555619726734355
2005	12.389196496124743
2006	9.383145305174812
2007	9.425802537210837
2008	8.582217583458977
2009	9.876309181128601
2010	9.630930654174538
2011	8.532194270195228
2012	9.239392613427809
2013	11.251095303903062
2014	9.52479189613231