Year	% of total fuel combustion
1971	32.82339271882261
1972	33.38533541341654
1973	33.985117162761235
1974	32.927624429471855
1975	33.7732256581971
1976	33.92388833848127
1977	34.707324547961996
1978	35.01044568245125
1979	34.673116596713385
1980	36.44538563054354
1981	36.00122747307928
1982	37.081558125380404
1983	38.288815081629785
1984	40.89487945529077
1985	41.571034605462145
1986	43.737252675623964
1987	43.516557471150605
1988	44.152828856941206
1989	43.32950834142467
1990	42.76347698000682
1991	41.1186343009436
1992	42.97060509293376
1993	45.33112884142826
1994	46.30903255387438
1995	46.65723133836862
1996	45.97581851756999
1997	48.175434557384605
1998	47.08237694465698
1999	46.301456218874115
2000	46.84554733818227
2001	47.21415670225657
2002	47.739802754409475
2003	48.92416828700242
2004	49.573694312556825
2005	48.80018805829807
2006	48.87642462905884
2007	46.89808166880196
2008	47.82504970178926
2009	48.401280489189254
2010	48.004526701810676
2011	48.27746838259322
2012	48.53374830817113
2013	48.850533738633345
2014	50.159275297396846