Year	% of total fuel combustion
1960	1.7678708685626443
1961	1.7322834645669294
1962	1.078582434514638
1963	1.3995801259622114
1964	1.1486486486486487
1965	0.8728179551122196
1966	1.106194690265487
1967	1.6295491580662684
1968	1.6914402870322909
1969	2.0680147058823533
1970	2.3809523809523814
1971	2.3053501522401048
1972	1.9108280254777072
1973	1.8835616438356164
1974	3.040987219039224
1975	5.5508474576271185
1976	7.419100236779795
1977	9.142212189616254
1978	11.262924667651406
1979	9.795067731851336
1980	12.118986412045539
1981	12.843676355066771
1982	14.268092105263158
1983	16.80327868852459
1984	15.848303393213573
1985	17.11472926921621
1986	22.65230562100303
1987	19.151251360174104
1988	21.38478182473855
1989	22.480620155038757
1990	26.620538965768386
1991	26.859344894026975
1992	35.66724436741767
1993	37.2870249017038
1994	37.49610713173467
1995	33.9171974522293
1996	30.747836835599507
1997	35.79595426561126
1998	37.006993006993014
1999	38.43052942757323
2000	31.15782867900847
2001	32.3905109489051
2002	32.98461538461538
2003	33.08613804905875
2004	33.0522765598651
2005	34.00985792983473
2006	34.18899858956276
2007	34.58229253399944
2008	34.61756373937678
2009	37.959069245864875
2010	36.77488025545503
2011	36.94390715667312
2012	36.533032185206096
2013	34.81481481481482
2014	36.47691871990937