Year	% of total fuel combustion
1971	38.495575221238944
1972	30.923694779116463
1973	26.235741444866918
1974	31.73431734317343
1975	23.588039867109636
1976	21.03448275862069
1977	18.263473053892216
1978	22.933333333333334
1979	26.840855106888355
1980	19.002375296912117
1981	15.977961432506888
1982	14.733542319749215
1983	16.363636363636363
1984	14.563106796116507
1985	14.150943396226415
1986	22.413793103448278
1987	20.955882352941174
1988	21.724137931034484
1989	22.36842105263158
1990	22.118380062305295
1991	22.28739002932551
1992	19.90521327014218
1993	22.4622030237581
1994	22.15447154471545
1995	21.843003412969285
1996	21.328671328671327
1997	20.833333333333336
1998	16.884816753926703
1999	15.046604527296935
2000	15.034965034965037
2001	14.57174638487208
2002	11.813471502590673
2003	9.854771784232364
2004	14.84375
2005	15.53672316384181
2006	15.616180620884288
2007	17.349607672188316
2008	15.121951219512194
2009	15.672306322350845
2010	13.85658914728682
2011	16.412213740458014
2012	16.43059490084986
2013	20.458265139116204
2014	34.20074349442378