Year	% of total fuel combustion
1960	18.01281125078264
1961	18.11896807720861
1962	18.717066585376475
1963	18.800273831935648
1964	18.347683476834764
1965	18.68557210000395
1966	19.080827712358523
1967	19.518363756322852
1968	18.905855982067806
1969	18.17210221200246
1970	17.75075414781297
1971	33.61770385737265
1972	33.26560955623326
1973	32.64071572696991
1974	32.83735976481501
1975	33.70190877757754
1976	34.253170153863415
1977	34.856098675194154
1978	34.72421459310865
1979	33.7465769243459
1980	33.11249290931248
1981	32.05612068593149
1982	32.05011860147029
1983	31.83435846811957
1984	32.14362775889103
1985	30.222377007797448
1986	29.937472226087504
1987	29.987741958703744
1988	29.83639226891575
1989	29.27601508154786
1990	23.569691747815206
1991	23.235718818692686
1992	23.121868613138687
1993	22.593411967444077
1994	22.766621130129778
1995	24.63263336235817
1996	23.217750987274393
1997	23.185553346587138
1998	23.261964652656093
1999	21.66213973472325
2000	21.442521581841355
2001	21.344682463205928
2002	21.265773023327846
2003	21.159809048764632
2004	23.07126944437623
2005	23.991456615377302
2006	23.97716213296948
2007	24.75239375948576
2008	25.17615111920716
2009	25.489184871729854
2010	25.562652368309365
2011	25.537184670758343
2012	24.644722334396597
2013	24.48522403867073
2014	24.66810784282855