Year	% of total fuel combustion
1971	12.102230017539465
1972	10.727190605239386
1973	10.73517126148705
1974	11.351679481991097
1975	12.016679302501894
1976	11.678832116788323
1977	12.03862326740383
1978	11.828859060402683
1979	11.187335092348285
1980	11.709601873536299
1981	11.606053209665609
1982	10.782265552460538
1983	10.733915292596185
1984	11.243500866551127
1985	11.15819209039548
1986	12.779459142829248
1987	13.591117917304746
1988	13.079091069226704
1989	13.02450486740517
1990	12.558925553677843
1991	10.77968661506513
1992	9.624326518562256
1993	9.494168523129341
1994	9.152542372881356
1995	8.901610468042273
1996	11.325950314277163
1997	10.221687754888633
1998	9.75049244911359
1999	12.243433328548871
2000	11.654111132573563
2001	11.371451885527774
2002	11.35805357351737
2003	10.580043665545524
2004	10.379803899470303
2005	12.193247323634363
2006	11.478620998432952
2007	11.132293471981512
2008	11.740452507344225
2009	9.875841152497394
2010	8.997204022868587
2011	8.98370161416706
2012	8.508041355542792
2013	8.36569248586416
2014	7.280978689818469