Year	% of total fuel combustion
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0.15698587127158525
1981	0
1982	0
1983	0
1984	0.14814814814814786
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0.489596083231334
1993	0.5082592121982213
1994	-1.7218099017139523E-16
1995	-1.7007092901733402E-16
1996	-1.6346039820747297E-16
1997	-1.523357607883036E-16
1998	0.1054852320675105
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	8.923474670662588E-17
2007	8.012579565712736E-17
2008	8.057238625066451E-17
2009	0.04957858205255315
2010	-1.2424160973871493E-16
2011	-0.04496402877697833
2012	7.870796170493681E-17
2013	1.209393273012153E-16
2014	7.474034795246906E-17