Year	% of total fuel combustion
1960	24.340309372156508
1961	23.78282679256418
1962	23.249078462348606
1963	23.239099185433634
1964	23.43151340996169
1965	23.453401943967982
1966	23.228258439526048
1967	23.480176211453745
1968	23.502257902659306
1969	23.78605330412559
1970	21.952765889998414
1971	21.78954791193293
1972	22.04436955911261
1973	22.78455421524362
1974	23.649082732529088
1975	18.13357592297779
1976	17.27447216890595
1977	18.26388387376327
1978	19.390039171796307
1979	20.888308295231877
1980	18.73968079251513
1981	20.08099427454266
1982	20.212056053977907
1983	20.24840910833397
1984	20.323820789590417
1985	18.930249367546082
1986	17.65080263064847
1987	18.77924580236719
1988	16.47707446437295
1989	16.2202787646898
1990	15.995857783914397
1991	15.341133166820036
1992	15.089090547790954
1993	15.382644892731347
1994	14.54626903878152
1995	15.813612181251147
1996	15.68366934319219
1997	15.358629426313566
1998	14.61418081136391
1999	15.729568354272919
2000	15.115487027060498
2001	14.659056773805949
2002	14.997601343247782
2003	14.926076456382162
2004	14.612244897959185
2005	14.597928267768397
2006	15.469239751705487
2007	15.46177370030581
2008	14.419623835899934
2009	13.803911735205615
2010	13.638503177218167
2011	14.382434826626172
2012	14.701358625993336
2013	14.288466478294376
2014	14.716192530672778