Year	% of total fuel combustion
1960	20.095408467501493
1961	19.19561243144424
1962	18.29465731246627
1963	20.25628388368655
1964	17.26618705035971
1965	16.596104995766296
1966	16.440366972477065
1967	17.849898580121707
1968	17.24678582627783
1969	17.50285062713797
1970	18.360914105594958
1971	19.745986101126288
1972	22.813455657492355
1973	21.85781990521327
1974	21.12115732368897
1975	22.45514003018615
1976	23.098845057747113
1977	22.306840210468014
1978	27.016294673421882
1979	27.930728241563056
1980	29.050747937928143
1981	28.057351700871525
1982	27.1461716937355
1983	26.55781006123184
1984	27.877820834283114
1985	24.447007023797042
1986	21.51910982099661
1987	23.389294190032523
1988	25.983817579992646
1989	24.687370600414077
1990	25.71383623063006
1991	26.567210326969153
1992	24.525210396961345
1993	23.460410557184748
1994	21.647994217564147
1995	21.914108813068108
1996	24.829021706809396
1997	25.685106382978724
1998	26.563029960429624
1999	23.39029082267738
2000	28.716954879745575
2001	23.180150079421594
2002	27.482738929554067
2003	29.346807986196698
2004	28.080934904384776
2005	25.45908691428836
2006	25.526052104208418
2007	23.076053791388855
2008	14.190260475651192
2009	15.299801301281802
2010	18.26814379380511
2011	18.2099090557955
2012	17.464565368222814
2013	16.278169014084508
2014	14.616912506919345