Year	% of total fuel combustion
1960	14.58955223880597
1961	10.693891676760686
1962	9.45945945945946
1963	9.466409514625521
1964	9.31889004303309
1965	8.72291904218928
1966	9.24347712075521
1967	10.33122085376061
1968	11.95069667738478
1969	9.71417149710174
1970	9.348364036293647
1971	9.870631720430106
1972	9.587835134053622
1973	7.105433144333596
1974	7.007425086184036
1975	7.484914623186545
1976	6.813569150478401
1977	7.0658755146524586
1978	7.30251537852488
1979	7.933146356819873
1980	6.954887218045112
1981	6.81913774973712
1982	7.189329863370203
1983	7.226479352916135
1984	7.677242459851155
1985	8.132947976878613
1986	8.10963230318069
1987	7.9112857944974735
1988	8.047879088752827
1989	7.67527303840153
1990	7.996051332675222
1991	8.6656842705709
1992	8.481297881928796
1993	8.653245567674048
1994	8.787054538748789
1995	8.30082832975413
1996	9.190602918234376
1997	8.528052245451846
1998	8.49562634098036
1999	8.293533469790008
2000	8.519728575018851
2001	8.801658801658801
2002	8.487010364786645
2003	8.5572632622707
2004	8.762531328320803
2005	8.689266552768036
2006	8.447193500738553
2007	7.934158327905736
2008	8.401950337434208
2009	9.275026267164234
2010	10.409191541339032
2011	9.493957703927492
2012	9.487789894025497
2013	10.179080352205538
2014	9.711625501099185