Year	% of total fuel combustion
1971	35.2622061482821
1972	37.99342105263158
1973	46.27791563275434
1974	43.04993252361673
1975	55.973154362416096
1976	52.09677419354839
1977	53.65497076023392
1978	50.57142857142857
1979	50.71428571428571
1980	59.78593272171254
1981	60.429447852760745
1982	49.55116696588868
1983	47.377938517179025
1984	48.46743295019157
1985	41.54175588865096
1986	37.10407239819004
1987	35.18123667377398
1988	32.03285420944559
1989	46.666666666666664
1990	51.65745856353592
1991	53.81414701803051
1992	36.70886075949367
1993	22.249690976514216
1994	32.02453987730061
1995	16.884661117717002
1996	19.84036488027366
1997	18.638392857142854
1998	18.92177589852008
1999	19.815195071868583
2000	20.32686414708887
2001	20.489296636085623
2002	19.157472417251753
2003	18.67704280155642
2004	30.73170731707317
2005	31.614785992217904
2006	43.95229982964225
2007	43.57446808510638
2008	43.50515463917526
2009	27.866666666666667
2010	25.82972582972583
2011	29.001367989056092
2012	29.694323144104807
2013	36.47540983606557
2014	35.70432357043236