Year	% of total fuel combustion
1971	8.2760731663553
1972	8.420027622936974
1973	8.702229072123753
1974	9.006801453461287
1975	8.59274880363371
1976	8.421709781887706
1977	8.096924665747139
1978	7.830239905222627
1979	8.024139069865194
1980	8.048017840045569
1981	8.201984468324833
1982	8.207233968198496
1983	8.244270573220131
1984	8.029810284135714
1985	8.215291719977142
1986	8.379110924296668
1987	8.35167428288778
1988	8.37553696108537
1989	8.58816193282551
1990	8.167775656003764
1991	8.195306784716099
1992	8.508555514215844
1993	8.77413336442838
1994	8.46635412771914
1995	8.421670868668349
1996	10.188491216081546
1997	9.624875641300743
1998	9.07965006451051
1999	9.854034807936165
2000	11.681949965235416
2001	11.521466695292256
2002	11.485365654491792
2003	11.014486237257097
2004	10.823289026847307
2005	10.063761989195797
2006	9.582007152273505
2007	9.434829942187852
2008	9.79627193097411
2009	9.658564109957469
2010	9.62665738598754
2011	9.555133510256958
2012	10.192986386741513
2013	10.560193716460564
2014	10.812006398807936