Year	% of total fuel combustion
1971	-4.3401994707785643E-16
1972	-0.07942811755361405
1973	2.6647058002715936E-16
1974	0.06565988181221229
1975	3.4245003844082556E-16
1976	3.145107718484863E-16
1977	-8.723180907769087E-16
1978	-0.05144032921810661
1979	0.045998160073597485
1980	4.1006549031110677E-16
1981	-4.927025257212233E-16
1982	-4.1800565686188125E-16
1983	-0.033955857385399295
1984	-2.7737084226144817E-16
1985	-1.6872690343847365E-16
1986	0.030931023816888368
1987	-0.029647198339757416
1988	-0.02804262478967972
1989	-2.653496712775231E-16
1990	-4.477608488103071E-16
1991	0.6674453529117305
1992	1.9395866454689987
1993	0.2657218777679365
1994	1.7952583253391805
1995	1.7343219806459718
1996	1.6613488832654861
1997	1.5523799732702785
1998	0.9724639164704674
1999	0.31038374717833006
2000	0.2781882987046856
2001	0.24914874179885377
2002	0.22930339210880088
2003	0.22597167821633027
2004	0.19107410945816858
2005	0.1989602721263077
2006	0.48216603820238596
2007	0.4606224019773058
2008	0.43622221054291244
2009	0.34163868763621374
2010	1.7120581572986355
2011	1.441554371670323
2012	1.6325472920445716
2013	1.5021048603138156
2014	1.3876292399782335