Year	% of total fuel combustion
1960	24.52059100911662
1961	22.610617246748024
1962	22.61961155850308
1963	21.857283418451008
1964	21.7495263015429
1965	21.496259351620946
1966	19.60054281638192
1967	18.260222545405348
1968	17.08590258066621
1969	18.486858116330005
1970	20.200708382526564
1971	15.24277384249273
1972	15.047714580057473
1973	14.659221375639287
1974	14.466340566290757
1975	14.460369454828852
1976	13.864804017779829
1977	13.262573047635913
1978	13.05436524982451
1979	13.284480288205675
1980	14.048714121815765
1981	14.26978231822151
1982	15.11584181168655
1983	14.051734936740573
1984	14.25038227476576
1985	15.605317697012588
1986	15.923201645114089
1987	16.866658974654822
1988	16.93940044079499
1989	15.737053800945574
1990	12.866697299229081
1991	14.628225591912742
1992	13.783748094260574
1993	14.344353228311514
1994	13.233612078387514
1995	13.093839604885874
1996	13.093851529455037
1997	12.719626049834687
1998	12.124605380318934
1999	12.795180034836244
2000	11.800578034682083
2001	12.195087320744005
2002	12.883479972215792
2003	12.917422051232373
2004	13.055312530378144
2005	13.239840681837173
2006	13.686868686868687
2007	12.008253468357179
2008	12.589618184849666
2009	13.733481166282102
2010	14.402609210165528
2011	13.029344198344242
2012	13.42639250312119
2013	13.648781553928531
2014	12.646858918341588