Year	% of total fuel combustion
1971	48.74578617480806
1972	48.376775683510346
1973	47.6936607494156
1974	48.25450833616876
1975	48.051569528509944
1976	48.89573415476525
1977	49.15325506233098
1978	47.368382685270234
1979	45.64585213517269
1980	44.07024490394486
1981	42.83692439241934
1982	43.29104789127005
1983	43.451002047193185
1984	43.91065041604636
1985	40.40745775639882
1986	40.12929269291522
1987	40.000546388372854
1988	39.07545983654763
1989	37.44550789094721
1990	35.89699124252146
1991	35.60935463959948
1992	35.4054444965528
1993	34.65567176186645
1994	34.93742458463538
1995	37.06409243941976
1996	33.72596262651936
1997	33.06440514690704
1998	34.12852661441682
1999	30.04972482379067
2000	28.936556282807334
2001	29.24229808492923
2002	28.172876218797356
2003	27.719598679372847
2004	31.376396526834053
2005	32.61740657585072
2006	31.845395137394977
2007	32.77123073569583
2008	33.933521778079076
2009	34.3439777632607
2010	33.44807676088776
2011	32.9571175428234
2012	32.053005636256714
2013	31.072303150505075
2014	31.71522709464992