Year	% of total fuel combustion
1960	17.67709538183767
1961	17.05288175876411
1962	17.446630800599404
1963	17.195802634516635
1964	17.14083223650906
1965	16.920035318054435
1966	16.157085159405344
1967	15.60921337503007
1968	15.870281085437188
1969	15.554184152061218
1970	15.20190833191344
1971	11.891817176557316
1972	11.860491022778458
1973	11.935152353707965
1974	12.145725886096784
1975	12.162464012707234
1976	12.151084939584305
1977	12.016532187335553
1978	12.125992874914015
1979	12.459188452200255
1980	12.63394254819912
1981	12.629098430135963
1982	12.54994296996418
1983	12.67881961278645
1984	12.355162284590655
1985	12.584019373352085
1986	12.840606240850517
1987	12.912286311239988
1988	12.814730727536766
1989	13.181071691497822
1990	12.90084794305729
1991	13.087053998940977
1992	13.400752750938759
1993	13.528661896537542
1994	13.334344899342613
1995	13.232977388077352
1996	14.423656345949668
1997	14.01599757996152
1998	13.56632017431204
1999	14.173809842378073
2000	15.033847730672903
2001	14.866686255972612
2002	14.64775555889674
2003	13.988393008089973
2004	13.483361462041277
2005	12.629326916970992
2006	12.076587667889516
2007	11.740693905786447
2008	11.942700145218534
2009	11.80598087393483
2010	11.572282329798151
2011	11.315248364071476
2012	11.815263615311999
2013	12.074494452951557
2014	12.266396240029644