Year	% of total fuel combustion
1971	2.618883528600965
1972	2.1261516654854713
1973	1.987179487179487
1974	2.1246458923512748
1975	2.9440628066732093
1976	2.859778597785978
1977	2.914389799635701
1978	3.344120819848975
1979	3.9215686274509802
1980	4.2675893886966545
1981	4.726368159203981
1982	4.663923182441701
1983	4.69208211143695
1984	4.185351270553064
1985	6.000000000000001
1986	6.293706293706294
1987	5.303030303030303
1988	4.624277456647399
1989	6.101694915254237
1990	7.894736842105263
1991	7.608695652173914
1992	8.041958041958043
1993	11.206896551724139
1994	10.266159695817493
1995	10.266159695817493
1996	10.526315789473685
1997	3.2319391634980996
1998	3.1307550644567224
1999	3.153988868274583
2000	3.0303030303030303
2001	2.992957746478874
2002	3.314917127071823
2003	3.308823529411764
2004	3.169014084507042
2005	3.005008347245409
2006	3.0560271646859083
2007	2.8124999999999996
2008	2.843601895734597
2009	3.0354131534569984
2010	4.337899543378996
2011	3.4545454545454546
2012	2.8634361233480177
2013	2.947845804988662
2014	2.736842105263158