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	17.849898580121703
1968	17.24678582627783
1969	17.50285062713797
1970	18.360914105594958
1971	38.45821486313207
1972	37.98567638563978
1973	37.32904511241206
1974	37.56037644043056
1975	37.87198023913206
1976	38.54170870495177
1977	39.0126872784816
1978	38.978783231083845
1979	37.82178217821782
1980	36.47952667012764
1981	35.4556557569178
1982	35.302053066828435
1983	35.412952367635
1984	35.72147651006712
1985	33.540348115482615
1986	32.64837198423235
1987	32.93532853183446
1988	32.64966348945007
1989	31.526680953339415
1990	22.975827308434
1991	22.636994000309322
1992	22.84557369941729
1993	22.807775863842043
1994	23.19650384934651
1995	25.579481531262445
1996	23.922132541670532
1997	23.81038381686695
1998	24.231224510626884
1999	22.07726881069374
2000	21.922708371534544
2001	21.758432222450566
2002	21.613118136889103
2003	21.561259011461733
2004	24.131044305139074
2005	25.314191129707815
2006	24.988579756803205
2007	25.943388789604064
2008	26.43096124070178
2009	27.067057421638275
2010	26.735404135546098
2011	26.681532755134363
2012	25.89575156544926
2013	25.443260350249055
2014	25.70215700901676