Year	% of total fuel combustion
1971	24.26385282581073
1972	23.470038249043775
1973	22.82614476413338
1974	22.662011997246537
1975	22.01906691843596
1976	20.333505687693894
1977	20.553159096675973
1978	21.616320125539428
1979	21.047347496084495
1980	20.902984504999623
1981	19.269748715812856
1982	15.475454634178082
1983	15.060938452163317
1984	13.815643079661772
1985	13.999095287512306
1986	13.127375499463993
1987	12.876681360913302
1988	12.663297211633187
1989	12.89429112284547
1990	12.1849135574367
1991	11.745171720702615
1992	11.552988970773386
1993	11.058728881737732
1994	10.798043368940768
1995	11.065735925842189
1996	11.31576104569515
1997	10.983776585528252
1998	11.178144994710062
1999	10.894396300016352
2000	10.67562104128296
2001	10.482534632465036
2002	10.444012142460132
2003	10.430251818925209
2004	10.504050492574908
2005	10.61894440430538
2006	10.396968854282536
2007	11.20669207292968
2008	12.032969891562056
2009	11.714593508562062
2010	11.994279477625982
2011	12.375137408593414
2012	12.23893765775425
2013	12.041825464517451
2014	11.478607891388197