Year	% of total fuel combustion
1971	15.789473684210526
1972	23.076923076923077
1973	48.717948717948715
1974	51.35135135135135
1975	34.375
1976	12.5
1977	17.24137931034483
1978	14.285714285714285
1979	40
1980	40.38461538461538
1981	36.36363636363637
1982	37.254901960784316
1983	50.68493150684932
1984	48.10126582278481
1985	18.181818181818183
1986	33.78378378378378
1987	34.66666666666667
1988	28.37837837837838
1989	6.896551724137932
1990	22.471910112359552
1991	23.008849557522126
1992	13.157894736842104
1993	14.615384615384617
1994	20.37037037037037
1995	19.886363636363637
1996	16.39344262295082
1997	13.809523809523808
1998	14.09090909090909
1999	34.5514950166113
2000	36.12903225806452
2001	37.91044776119403
2002	23.970037453183522
2003	26.55172413793104
2004	24.444444444444443
2005	33.22475570032574
2006	24.8
2007	31.3953488372093
2008	26.041666666666668
2009	22.15743440233236
2010	29.85436893203883
2011	32.95454545454545
2012	34.80885311871227
2013	27.77777777777778
2014	32.71500843170321