Year	PPP $ per kg of oil equivalent
1990	1.1760667126218387
1991	1.1667576455091049
1992	1.1255450390441013
1993	1.0821314705470124
1994	1.058991102155721
1995	1.1678870218066812
1996	1.1696255405058305
1997	1.2306218374731983
1998	1.1678348144550847
1999	1.202951738838167
2000	1.2884964821709155
2001	1.3639386184314957
2002	1.382793564824876
2003	1.5201975034375748
2004	1.7017103455425326
2005	2.025183067745654
2006	2.1957977222334812
2007	2.4861068517682963
2008	2.6511152458000744
2009	3.2457856636621965
2010	3.61626498551669
2011	3.6217443230466624
2012	3.7281619644289377
2013	4.440116915219104