Year	% of total fuel combustion
1971	43.63262155904297
1972	42.54452926208651
1973	43.19180087847731
1974	43.775388291517324
1975	45.50509731232623
1976	45.1716247139588
1977	46.21312197269924
1978	44.63087248322148
1979	44.20093095422808
1980	31.971326164874554
1981	31.147842056932966
1982	30.071915215745648
1983	30.096719135217143
1984	31.470965378274407
1985	31.39235855988244
1986	30.999806613807774
1987	30.885650224215244
1988	30.780559646539025
1989	31.768213154462455
1990	28.852817800474195
1991	29.822732012513036
1992	29.977678571428573
1993	25.773672055427255
1994	28.6770140428677
1995	25.327510917030565
1996	27.19084712755599
1997	26.254262055528493
1998	24.53259221829207
1999	23.615761009528715
2000	26.626898047722342
2001	22.83190578158458
2002	24.667931688804554
2003	23.475935828877002
2004	22.838994752830708
2005	22.496644295302016
2006	22.92295037016726
2007	23.059680582796304
2008	22.501411631846413
2009	19.631901840490798
2010	19.589120370370367
2011	20.426179604261797
2012	21.991037131882205
2013	22.089364380113278
2014	24.616433685646097