Year	% of total fuel combustion
1960	29.658547875454385
1961	30.259947509330946
1962	29.893661333398672
1963	28.715136465015753
1964	30.47108756843015
1965	29.887881641736858
1966	29.9971952131638
1967	30.5396166215087
1968	30.921556228575234
1969	31.125320706059416
1970	32.51934290409972
1971	33.275209845274624
1972	33.730040817603175
1973	34.037086320381476
1974	35.56347016057106
1975	35.15422919236128
1976	36.799081185844514
1977	36.542537698658734
1978	37.020384443202445
1979	37.12873278953679
1980	38.61583519972435
1981	39.105755055890306
1982	39.92129747735544
1983	39.937352939433275
1984	39.530917470242024
1985	39.124012456783625
1986	39.206088385367124
1987	39.00319877968263
1988	38.99927280223084
1989	40.53516295025729
1990	42.11451437974494
1991	42.14032139420072
1992	42.817607184049095
1993	42.04155640497891
1994	42.248113332450686
1995	41.91061679443923
1996	41.507469096942344
1997	41.22366317712527
1998	41.381721515782615
1999	41.006454858938014
2000	41.542056217864896
2001	41.37064620476943
2002	42.148466350139415
2003	42.3443032182175
2004	42.285598669915636
2005	42.36163167493995
2006	42.73111647078942
2007	44.08358629920884
2008	42.72429301013797
2009	42.21830974349541
2010	42.25065537278114
2011	43.177805550596126
2012	43.23710463436694
2013	41.945290851556486
2014	41.59511654524645