Year	% of total fuel combustion
1971	10.337698139214336
1972	10.559886605244508
1973	8.782051282051283
1974	8.852691218130312
1975	11.481844946025516
1976	12.546125461254615
1977	12.659380692167577
1978	18.12297734627832
1979	16.884531590413946
1980	17.87773933102653
1981	17.910447761194032
1982	18.51851851851852
1983	19.941348973607038
1984	18.98355754857997
1985	24.66666666666667
1986	21.21212121212121
1987	24.242424242424242
1988	28.61271676300578
1989	30.84745762711864
1990	33.83458646616541
1991	36.23188405797102
1992	37.76223776223777
1993	36.63793103448276
1994	43.346007604562736
1995	43.346007604562736
1996	43.233082706766915
1997	22.813688212927758
1998	23.020257826887665
1999	24.30426716141002
2000	24.242424242424242
2001	24.471830985915492
2002	25.59852670349908
2003	25.551470588235293
2004	25
2005	24.20701168614357
2006	25.46689303904924
2007	24.375
2008	25.118483412322274
2009	25.801011804384487
2010	35.61643835616439
2011	28.545454545454547
2012	23.348017621145374
2013	24.263038548752835
2014	22.947368421052634