Year	% of total fuel combustion
1971	7.78816199376947
1972	5.865102639296188
1973	4.185022026431718
1974	4.683840749414521
1975	5.919003115264798
1976	5.956112852664576
1977	8.259587020648967
1978	10.38961038961039
1979	11.78343949044586
1980	6.811989100817439
1981	6.983240223463687
1982	7.336956521739131
1983	7.733333333333333
1984	9.00900900900901
1985	12.311557788944723
1986	11.989795918367347
1987	16.333333333333332
1988	12.785388127853883
1989	11.139240506329113
1990	9.640831758034027
1991	12.262156448202958
1992	11.512415349887133
1993	28.802588996763756
1994	14.59694989106754
1995	20.649651972157777
1996	24.87804878048781
1997	22.090729783037478
1998	20.12987012987013
1999	22.200392927308453
2000	26.824817518248175
2001	25.24916943521595
2002	28.82037533512064
2003	30.89005235602094
2004	29.67818831942789
2005	27.89046653144016
2006	27.94476035743298
2007	26.490566037735846
2008	27.126917712691768
2009	22.389078498293514
2010	11.022044088176353
2011	15.691868758915836
2012	15.457875457875456
2013	15.74279379157428
2014	16.49175412293853