Year	% of total fuel combustion
1971	32.053973013493255
1972	32.724107919930375
1973	32.34220135628587
1974	31.613390385099418
1975	32.659698025551684
1976	34.48944420508402
1977	37.30807577268196
1978	39.42255311421827
1979	39.25021795989538
1980	39.95029512270891
1981	38.961038961038966
1982	38.38023516977144
1983	38.54605851539542
1984	37.81735505873437
1985	35.075236206695436
1986	34.55807075418041
1987	31.995563174347076
1988	32.60723539007773
1989	31.576072111444965
1990	17.102031703505247
1991	18.74096129306678
1992	20.05232123577776
1993	19.321073803464415
1994	19.041705917615825
1995	21.38050792272628
1996	23.9650048139311
1997	25.366800048502487
1998	23.48357524828113
1999	23.787696896940595
2000	23.850802100568302
2001	24.7577400734651
2002	24.62747778537252
2003	25.84671457552522
2004	25.573824946022256
2005	24.31330969815447
2006	22.490363123967477
2007	22.559176241602305
2008	23.96060922706691
2009	25.001653111155193
2010	26.00879586530127
2011	24.509356458238248
2012	24.686817950787816
2013	25.451413454735615
2014	25.03277339105515