Year	% of total fuel combustion
1971	27.518959913326107
1972	25.523012552301257
1973	22.01453790238837
1974	32.36363636363637
1975	27.45638200183655
1976	30.317460317460316
1977	31.546391752577318
1978	29.987046632124354
1979	18.149964961457606
1980	14.726027397260275
1981	14.955640050697086
1982	16.75423234092236
1983	14.826175869120656
1984	15.492957746478872
1985	12.690582959641256
1986	12.470308788598574
1987	12.247838616714695
1988	13.185041908446163
1989	12.326227988878594
1990	8.97897897897898
1991	5.963556046383214
1992	9.106529209621993
1993	6.876591803658255
1994	9.083424807903404
1995	8.023001095290251
1996	7.521998296906046
1997	7.936507936507938
1998	10.644460535843592
1999	13.157894736842104
2000	10.585027268220127
2001	13.392857142857142
2002	11.316051844466601
2003	9.039943938332165
2004	12.07528721583965
2005	9.484635857730463
2006	13.185255198487713
2007	14.172155348625937
2008	15.262543757292882
2009	15.916955017301039
2010	13.360323886639677
2011	15.512708150744961
2012	15.945886005766244
2013	15.830618892508145
2014	16.729244889445138