Year	% of total fuel combustion
1960	24.543659394114524
1961	22.69394951744617
1962	22.666898924356573
1963	22.3087455074448
1964	21.992619926199257
1965	21.351554168806032
1966	19.458099919972565
1967	18.510373139799135
1968	17.38582235920426
1969	18.913754574602457
1970	20.45940170940171
1971	15.522608374758502
1972	15.438468565529615
1973	15.06357337941889
1974	14.809121188829108
1975	15.081703450757294
1976	14.701628180840714
1977	14.656580289918878
1978	14.437087562307736
1979	14.305190924419966
1980	13.916158724901894
1981	14.194478242478993
1982	14.39961398252311
1983	14.32764329964931
1984	14.377574996408326
1985	14.949616279936148
1986	14.584616185181652
1987	14.549489351789415
1988	14.643737723282042
1989	14.180256015570713
1990	12.352009011888454
1991	12.078234256069141
1992	11.41448624368332
1993	11.631082534277267
1994	11.344716299965677
1995	11.412374744013245
1996	10.833588985023459
1997	11.157984129932858
1998	10.197473583254814
1999	10.681589550470074
2000	10.24709870445517
2001	10.041230917769688
2002	9.821822217492436
2003	9.46721445251263
2004	9.243016280086175
2005	8.847494515164989
2006	8.661140830162772
2007	8.419504140232734
2008	8.300699661567865
2009	7.985360821973347
2010	7.557450657286351
2011	7.388993445207035
2012	7.288892452086284
2013	7.201374574859963
2014	7.183496483045877