Year	% of total fuel combustion
1971	22.413793103448278
1972	23.963133640552996
1973	22.46696035242291
1974	18.497109826589597
1975	25.301204819277107
1976	29.381443298969067
1977	30.33175355450237
1978	29.14798206278027
1979	30.45267489711934
1980	30.739299610894943
1981	26.48221343873518
1982	24.902723735408564
1983	24.427480916030532
1984	25.182481751824813
1985	23.55072463768116
1986	26.072607260726077
1987	28.412256267409475
1988	28.767123287671236
1989	25.721784776902883
1990	20.308483290488432
1991	29.054054054054053
1992	23.36842105263158
1993	23.886639676113358
1994	23.540856031128403
1995	24.356435643564357
1996	25.420560747663558
1997	23.400365630712983
1998	22.547332185886404
1999	22.240527182866558
2000	22.063492063492063
2001	21.486268174474958
2002	20.82018927444795
2003	19.373219373219374
2004	20.115774240231545
2005	14.184397163120568
2006	12.376933895921237
2007	12.129380053908356
2008	11.609498680738787
2009	10.133333333333333
2010	9.228650137741047
2011	8
2012	7.066052227342551
2013	9.608540925266905
2014	11.631944444444446