Year	% of total fuel combustion
1971	19.79522184300341
1972	19.924812030075188
1973	18.050541516245488
1974	17.228464419475657
1975	16.806722689075627
1976	16.872427983539094
1977	19.913419913419915
1978	24.12060301507538
1979	24.86772486772487
1980	23.93162393162393
1981	26.108374384236456
1982	27.419354838709676
1983	28.488372093023255
1984	31.292517006802722
1985	30.66666666666667
1986	31.292517006802722
1987	31.972789115646254
1988	32.432432432432435
1989	32.87671232876712
1990	10.185185185185185
1991	14.444444444444446
1992	8.333333333333332
1993	4.6875
1994	2.8037383177570088
1995	2.608695652173913
1996	2.7522935779816513
1997	2.5
1998	1.724137931034483
1999	1.7391304347826086
2000	3.787878787878788
2001	3.8461538461538463
2002	2.9197080291970803
2003	1.8072289156626504
2004	2.366863905325444
2005	1.3245033112582782
2006	1.2345679012345678
2007	0.5076142131979696
2008	1.0256410256410255
2009	0.904977375565611
2010	0.8403361344537816
2011	4.964539007092198
2012	2.2900763358778624
2013	7.118644067796609
2014	19.896640826873384