Year	% of total fuel combustion
1971	29.48143405889885
1972	28.622439391091902
1973	27.39795918367347
1974	28.03898635477583
1975	29.140648230746358
1976	29.663819233948747
1977	27.518475301439132
1978	28.50426094622392
1979	27.545301191707022
1980	24.913224150574433
1981	25.79278294149809
1982	25.310464611376464
1983	28.18965902489163
1984	26.14661086421884
1985	26.497428239588515
1986	23.414369709353235
1987	24.322373696872493
1988	22.380664652567976
1989	22.1848996106573
1990	20.734223537197806
1991	18.916560625340846
1992	18.613270005757048
1993	17.51663747810858
1994	16.462941404734185
1995	16.9310534267271
1996	18.002494420375477
1997	17.014028676721065
1998	16.31813705613161
1999	15.435242264510556
2000	14.709971636727657
2001	13.27951620062139
2002	13.980978260869566
2003	13.603074845478627
2004	14.286439430471306
2005	14.293715148416004
2006	15.574021327181562
2007	14.387622753381507
2008	14.88524893577642
2009	12.30311474248471
2010	14.19340107318187
2011	14.920258336628441
2012	13.436325496023075
2013	14.670505009930595
2014	13.447971781305116