Year	% of total fuel combustion
1960	23.1814548361311
1961	24.258667883211675
1962	26.841329966329962
1963	28.797198826535443
1964	24.036237471087123
1965	25.009416195856875
1966	25.321046956180766
1967	26.572127139364298
1968	27.170718674859735
1969	26.309045869992314
1970	27.473893585280955
1971	25.932835820895523
1972	26.48737393479791
1973	26.62005713426552
1974	24.360051959960263
1975	28.82251082251082
1976	25.034111886989326
1977	25.26546161951852
1978	26.602439592883222
1979	27.330460421864366
1980	25.55378486055777
1981	25.08041380509432
1982	24.222344929136757
1983	24.664664664664667
1984	24.46975648075412
1985	27.974244675581968
1986	28.98064006321612
1987	28.39091806515301
1988	25.09952422565298
1989	23.09756565075714
1990	23.143529411764703
1991	24.747565813198705
1992	25.059556532893527
1993	24.810977317278077
1994	23.135328271549795
1995	24.303502642658785
1996	26.975430185771764
1997	25.686136523574948
1998	24.898907338897015
1999	24.360341151385928
2000	23.21193505923651
2001	24.001395429966863
2002	24.446511627906975
2003	25.140211875723317
2004	25.859895551953898
2005	26.63124533929903
2006	24.728704503985405
2007	22.398235412071386
2008	25.298766383962988
2009	25.01812907904279
2010	25.353583293782634
2011	23.702200384533214
2012	24.961948249619482
2013	27.077087794432547
2014	22.985347985347985