Year	% of total fuel combustion
1960	13.675213675213676
1961	16.521739130434785
1962	16.12903225806452
1963	17.322834645669293
1964	18.6046511627907
1965	20.000000000000004
1966	21.333333333333332
1967	18.30985915492958
1968	18.120805369127517
1969	15.789473684210526
1970	15.151515151515154
1971	21.66030534351145
1972	23.03003918154114
1973	29.01833872707659
1974	29.289170078154076
1975	34.785639595677935
1976	31.56779661016949
1977	30.01269035532995
1978	29.067979083358967
1979	31.030577576443942
1980	28.61396859772604
1981	29.978328918853844
1982	28.014354066985643
1983	28.06267806267806
1984	22.696990581208365
1985	20.396404701544135
1986	19.729965156794425
1987	19.373942470389167
1988	18.56371274254851
1989	19.524262607040914
1990	16.780897634313508
1991	15.977191413237925
1992	14.608837588900549
1993	13.738441215323647
1994	14.571733206966
1995	13.63851431275136
1996	14.427973294104335
1997	13.7527352297593
1998	13.792372881355934
1999	13.28627776624455
2000	15.146246676211904
2001	15.602698210968816
2002	16.32028205604008
2003	14.0133951571355
2004	15.655511975298339
2005	15.087099992325992
2006	16.175332442130443
2007	18.359654253590694
2008	17.459607893224344
2009	13.901052218809228
2010	12.903420038535646
2011	11.359934853420196
2012	13.74513077351141
2013	14.315474600715776
2014	14.909615285574496