Year	constant 2021 PPP $ per kg of oil equivalent
1990	12.729179474672035
1991	12.730769835506024
1992	12.80795892183686
1993	13.15525934408707
1994	13.28239661115783
1995	13.146944736671102
1996	13.157135726783977
1997	13.28763912626874
1998	13.274299829553483
1999	13.137944765107427
2000	13.488482071351608
2001	13.372876351195652
2002	13.29353549651977
2003	13.139675412502559
2004	13.30768879149681
2005	13.283976802706142
2006	13.46144462114439
2007	13.812490799059956
2008	13.941139135464795
2009	13.739209301965484
2010	13.98435326887608
2011	14.207547519517304
2012	14.040086359616291
2013	14.059347509588399
2014	13.9388308930872