Year	% of total fuel combustion
1971	0.15250544662309315
1972	0.27431947668284407
1973	0.25445292620865145
1974	0.15999999999999995
1975	0.05352363960749353
1976	0.01682085786375088
1977	0.04870920603994141
1978	0.07463800567248864
1979	0.03929787791459276
1980	0.05998800239951972
1981	0.11831519167061022
1982	0.12883579292574399
1983	0.17669925786311722
1984	0.14114326040931516
1985	0.1644736842105271
1986	0.10604453870625666
1987	0.09527212099559342
1988	0.09423960419366155
1989	0.043677658877484205
1990	0.010688328345447019
1991	0.010830715910321441
1992	0.17983708875489302
1993	0.3393890996206833
1994	0.46636237348680315
1995	0.5185255020269633
1996	0.1578116780641769
1997	0.1683785149014989
1998	0.15041363750313338
1999	0.5031101353823642
2000	0.4389740058529869
2001	0.45413997242721627
2002	0.4401336702257727
2003	0.17162471395881004
2004	0.2194529351830079
2005	0.9771749434842849
2006	0.11257880516361486
2007	0.3545279383429679
2008	5.572709371942058E-16
2009	0
2010	-0.005831923951711804
2011	4.4027350613026695E-16
2012	-0.005925925925925536
2013	0.0064119004873044415
2014	-4.297914799503799E-16