Year	% of total fuel combustion
1971	22.804329087252178
1972	23.17596566523605
1973	23.90240111896807
1974	24.180837826627954
1975	24.24557116676848
1976	24.98664387220857
1977	25.571867531580743
1978	26.089975006942517
1979	24.959143650923355
1980	25.72460859092734
1981	25.895431780239793
1982	25.341478481707735
1983	24.85431060378492
1984	24.89580986708718
1985	26.37963209810717
1986	25.78651094276094
1987	25.626511732289355
1988	25.126653701169296
1989	25.407254072540727
1990	26.443649685973483
1991	26.100104275286757
1992	25.601926163723913
1993	25.84791531648304
1994	25.54211634200942
1995	25.04429237846009
1996	25.47308049852679
1997	24.328516975445435
1998	26.17801047120419
1999	26.831665737507702
2000	27.272341268717973
2001	26.398035050451405
2002	26.8308406395049
2003	26.59321884853587
2004	26.461766470235364
2005	26.276848083911823
2006	26.248464789025583
2007	25.595036210921133
2008	25.698619086945662
2009	26.372479935574205
2010	26.157821506658717
2011	26.122175582745378
2012	26.61436643569318
2013	25.96819632068427
2014	26.102919990450555