Year	% of total fuel combustion
1971	32.98611111111111
1972	32.98611111111111
1973	37.5366568914956
1974	34.70437017994858
1975	34.92063492063492
1976	33.119658119658126
1977	32.29166666666667
1978	31.213872832369944
1979	28.771929824561397
1980	31.762917933130698
1981	30.298273155416013
1982	28.77906976744186
1983	24.416796267496114
1984	22.065727699530516
1985	16.883116883116884
1986	16.901408450704224
1987	18.829787234042552
1988	16.08606557377049
1989	15.347950428979981
1990	20.2276707530648
1991	14.046511627906977
1992	12.691652470187393
1993	11.689351481184948
1994	14.105419450631029
1995	20.145631067961165
1996	17.756448710257946
1997	19.370330843116328
1998	15.076436478650502
1999	14.489069649211997
2000	19.149952244508118
2001	18.397745571658618
2002	18.651092690278826
2003	19.755307664627566
2004	13.858055835856037
2005	14.710485133020345
2006	15.061096902529128
2007	16.085790884718502
2008	17.1764130168828
2009	18.53281853281853
2010	18.39518555667001
2011	17.37987987987988
2012	17.905759162303667
2013	17.78523489932886
2014	16.348161233338683