Year	% of total fuel combustion
1960	32.385520155304334
1961	31.421076642335766
1962	30.250420875420875
1963	29.25144317213968
1964	31.43793369313801
1965	29.199623352165727
1966	30.153906479756888
1967	29.486552567237162
1968	27.687238400569953
1969	26.889894934654485
1970	25.00414387535223
1971	27.264246947082764
1972	28.097881322805097
1973	29.10840475116524
1974	32.329792924276
1975	28.5974025974026
1976	30.997672365358376
1977	31.29610115911486
1978	30.914458861005357
1979	31.806154078778253
1980	33.808764940239044
1981	34.63444318873338
1982	33.50819068654519
1983	32.27227227227227
1984	30.77376276512176
1985	26.79544328875681
1986	25.138285262742006
1987	26.29812438302073
1988	27.614331488494038
1989	28.407130534790102
1990	29.797647058823536
1991	28.993869455463393
1992	28.724573941726224
1993	29.151498179781576
1994	29.88834301027244
1995	29.714234524769328
1996	28.310932283194933
1997	27.647783251231523
1998	28.443603200550633
1999	26.51030561478323
2000	27.38043001316367
2001	25.536368393511253
2002	27.4046511627907
2003	27.19665271966527
2004	26.949396722492345
2005	27.992170022371365
2006	28.32036876980697
2007	29.38640465209545
2008	26.715497301464918
2009	26.15767119030353
2010	27.50830564784053
2011	27.857295449690234
2012	27.65818656229615
2013	25.406852248394003
2014	25.8470695970696