Year	% of total fuel combustion
1960	20.345601353712592
1961	20.23280905211908
1962	20.762767178063744
1963	20.67555202427898
1964	19.48226447752956
1965	19.226049544533055
1966	18.719982785826996
1967	18.438110888391982
1968	18.095930137919268
1969	18.097988742871923
1970	19.894454141695146
1971	19.571054732357446
1972	19.36114346431272
1973	18.39094829674856
1974	17.723711372837617
1975	18.039822805377153
1976	18.141900838747464
1977	17.37118444619827
1978	17.460241814986023
1979	16.752040292699142
1980	16.02041633118152
1981	15.603794468235527
1982	15.953899449635019
1983	15.612466745432771
1984	15.97231751741347
1985	16.090463704511436
1986	16.169071427059666
1987	15.847674273307296
1988	15.52804781989228
1989	14.79277697210037
1990	14.093089869462194
1991	14.475393663646017
1992	14.225525464417585
1993	14.46528184739006
1994	13.77160321436044
1995	13.84842534140713
1996	14.322796377000781
1997	13.596245030575991
1998	12.92927290598079
1999	13.063225564694465
2000	12.76427092953919
2001	12.856580179013655
2002	12.758475453373519
2003	12.921202858389222
2004	12.649231789818252
2005	12.498043936668479
2006	11.931942988270812
2007	11.40870239197365
2008	12.15258219295879
2009	12.712211780504303
2010	12.413771986582232
2011	11.830729326225924
2012	11.754994644244897
2013	12.277212531367189
2014	11.849179482974712