Year	% of total fuel combustion
1965	22.62859378055936
1966	21.022400919012064
1967	19.759679572763684
1968	19.780635400907716
1969	19.35308013810649
1970	20.859628176701346
1971	18.848515015762402
1972	18.04571796522859
1973	18.10928797230167
1974	17.156150043617334
1975	16.626300042741132
1976	17.05288985823337
1977	16.20743436443982
1978	17.258045502770248
1979	18.201438848920862
1980	18.141110976642867
1981	18.426526367306987
1982	18.957115009746587
1983	19.02880448636248
1984	19.1055900621118
1985	22.113576532531027
1986	21.29535002554931
1987	22.84847718943511
1988	24.237948167047136
1989	24.05809014933553
1990	25.77649208282582
1991	28.19098644815632
1992	24.56263121063681
1993	26.093777235488936
1994	26.58540893835012
1995	25.257731958762893
1996	25.544899738448123
1997	24.395486297689416
1998	22.55076594228714
1999	23.29805996472663
2000	24.751360480390318
2001	25.6872383032951
2002	25.968992248062015
2003	27.31595632264882
2004	28.254948247684762
2005	29.51388888888889
2006	27.01255539143279
2007	22.772277227722775
2008	23.420289855072465
2009	25.75208022189034
2010	26.697498423376075
2011	26.338797814207656
2012	24.988146040777618
2013	24.91375061606703
2014	22.591857000993045