Year	% of total fuel combustion
1971	37.103448275862064
1972	32.60553129548763
1973	38.951310861423224
1974	30.809399477806785
1975	36.959553695955364
1976	41.478696741854634
1977	41.534008683068016
1978	44.41301272984441
1979	44.15954415954416
1980	43.03638644918444
1981	48.42767295597484
1982	48.84020618556701
1983	45.94257178526841
1984	38.31325301204819
1985	34.018499486125386
1986	29.185727355901193
1987	23.40277777777778
1988	23.592302209550965
1989	24.496877168632892
1990	29.16923076923077
1991	27.814938684503904
1992	25.414364640883974
1993	23.155368926214752
1994	15.399484536082475
1995	17.42876076872101
1996	17.301038062283737
1997	17.040358744394617
1998	17.547723935389136
1999	20.11680726800779
2000	22.272385252069228
2001	18.938835666912304
2002	18.627450980392155
2003	20.37962037962038
2004	16.30094043887147
2005	15.87147030185005
2006	21.861924686192467
2007	23.700623700623698
2008	17.986577181208055
2009	8.774373259052926
2010	13.109425785482124
2011	13.188798554652212
2012	16.695804195804197
2013	8.503401360544217
2014	8.96431679721497