Year	% of total fuel combustion
1971	32.244985061886474
1972	31.5824093215561
1973	31.071428571428573
1974	31.048732943469787
1975	31.72019030627416
1976	31.92339487462111
1977	31.90716971347076
1978	31.389950044078752
1979	32.8073134896882
1980	33.028599364458564
1981	34.381264807727355
1982	32.66608771168042
1983	29.972739866827542
1984	30.36199680717953
1985	29.421768707482993
1986	29.243984821316875
1987	28.84923817161187
1988	29.518630412890236
1989	30.769524391174897
1990	32.49892941955075
1991	32.49590983457553
1992	32.2646804835924
1993	32.13309982486865
1994	31.499805975941015
1995	30.689465732729015
1996	30.09715110936064
1997	29.633644049425534
1998	28.46840062561548
1999	30.096191071800828
2000	29.36432901395918
2001	29.9239902352419
2002	29.828804347826086
2003	30.21866722069288
2004	31.151493616913278
2005	31.706723159714613
2006	32.341517384242366
2007	33.61821382249398
2008	34.971312233944104
2009	34.873780905377004
2010	34.37835369334399
2011	33.31136593295549
2012	33.31876584214666
2013	33.61228269844458
2014	35.09236053095702