Year	% of total fuel combustion
1971	4.972375690607738
1972	5.252918287937742
1973	6.085192697768764
1974	4.584527220630373
1975	4.721549636803876
1976	4.843918191603875
1977	4.870775347912525
1978	5.024630541871921
1979	4.12603150787697
1980	4.870129870129869
1981	4.906204906204906
1982	10.548523206751055
1983	14.373401534526856
1984	16.515426497277677
1985	10.803891449052738
1986	17.119694802098238
1987	22.65657839428331
1988	23.577568563241915
1989	16.75062972292191
1990	22.55694342395298
1991	24.714573539288114
1992	20.084865629420086
1993	16.383581033262555
1994	11.602585913576045
1995	11.793059125964012
1996	9.845165059888988
1997	8.142567371776298
1998	8.368869936034114
1999	7.193654266958426
2000	6.376654958119427
2001	9.719722293648756
2002	6.206030150753769
2003	6.871564217891053
2004	4.919962335216573
2005	5.444340505144996
2006	5.0291159343568
2007	5.0008390669575435
2008	4.809259863058362
2009	4.041651959054008
2010	2.7882037533512047
2011	2.8681424446583246
2012	2.7893639207507817
2013	3.0748663101604286
2014	7.290533188248095