Year	% of total fuel combustion
1971	27.1505376344086
1972	26.811594202898547
1973	26.004728132387704
1974	24.89539748953975
1975	25.413223140495866
1976	26.7056530214425
1977	28.745644599303137
1978	30.5111821086262
1979	31.420765027322407
1980	34.343434343434346
1981	33.90663390663391
1982	34.42622950819672
1983	35.52631578947369
1984	34.148936170212764
1985	32.40165631469979
1986	33.36693548387097
1987	36.10832497492477
1988	36.94444444444444
1989	34.133790737564325
1990	32.81378178835111
1991	35.035913806863526
1992	34.939759036144586
1993	34.306569343065696
1994	34.517766497461935
1995	33.71347113328582
1996	33.852403520649965
1997	34.954604409857325
1998	35.798632691112495
1999	36.76731793960924
2000	35.84798638684062
2001	37.189189189189186
2002	37.3110151187905
2003	31.314784506273874
2004	30.987394957983195
2005	31.63841807909605
2006	32.98611111111111
2007	34.239389604196475
2008	34.489311163895486
2009	36.062470421202086
2010	36.23872906826964
2011	37.41007194244605
2012	38.68768640818066
2013	39.06976744186047
2014	38.784486205517794