Year	% of total fuel combustion
1960	25.580258059662192
1961	26.487412103326406
1962	26.77765046842353
1963	23.646514595629288
1964	27.22063037249284
1965	24.228807384017486
1966	23.447830499092838
1967	24.18776770884933
1968	22.46169388785991
1969	22.837873578418407
1970	24.274322169059012
1971	25.89021998535006
1972	25.357957136342907
1973	27.20217634281617
1974	27.62451519600324
1975	27.490247074122237
1976	31.332224406472097
1977	29.75484733675061
1978	28.57570445119083
1979	30.122259696458688
1980	30.121302685360167
1981	27.192098862491708
1982	28.380702970551237
1983	25.48820287839067
1984	22.2972412075597
1985	20.164913278362242
1986	16.95312271249964
1987	15.866762177650429
1988	16.677162992952468
1989	19.59273685416428
1990	18.42836468885673
1991	20.027553418514817
1992	17.675389755011135
1993	15.06953817264245
1994	15.08090229148664
1995	16.274669616347442
1996	16.69402632091483
1997	16.015046164367945
1998	19.026263494280034
1999	17.689432180959916
2000	19.04539843642847
2001	17.07237557052815
2002	17.91390728476821
2003	18.451718049708003
2004	18.23282287572842
2005	19.83694184979213
2006	19.25858199650902
2007	20.336677435810234
2008	19.70556223864353
2009	19.540505683692754
2010	20.315808045165845
2011	18.32179094862297
2012	17.43022136669875
2013	16.9930312490146
2014	13.795155418650237