Year	% of total fuel combustion
1971	40.17857142857142
1972	41.37931034482759
1973	41.73228346456693
1974	40
1975	39.097744360902254
1976	38.02816901408451
1977	36.70886075949367
1978	39.24050632911392
1979	38.69047619047619
1980	36.470588235294116
1981	39.13043478260869
1982	40.25157232704402
1983	41.47727272727273
1984	40.86021505376344
1985	46.10778443113773
1986	51.17647058823529
1987	49.473684210526315
1988	47.36842105263158
1989	46.982758620689665
1990	47.70642201834862
1991	47.68518518518518
1992	47.15447154471544
1993	50.76923076923077
1994	51.33333333333333
1995	43.417366946778714
1996	42.61363636363637
1997	45.58011049723756
1998	42.36111111111111
1999	48.62385321100917
2000	46.993318485523375
2001	42.53308128544423
2002	40.213523131672595
2003	36.85897435897436
2004	33.14366998577525
2005	31.424581005586592
2006	35
2007	39.4088669950739
2008	37.69035532994924
2009	41.08108108108108
2010	40.735694822888284
2011	37.82816229116945
2012	39.52095808383233
2013	39.171597633136095
2014	39.54285714285714