Year	% of total fuel combustion
1960	19.7376267143709
1961	19.68312004875076
1962	21.64058283864004
1963	16.21488417939872
1964	21.672661870503596
1965	22.81964436917866
1966	24.844036697247702
1967	22.718052738336713
1968	23.26748196926936
1969	26.795895096921324
1970	26.2936695560809
1971	22.18658937885502
1972	22.711422599286855
1973	23.510750793091294
1974	23.693843149987327
1975	23.694310095563335
1976	23.873224160174757
1977	24.080992072130265
1978	24.694959256967564
1979	25.70907000053414
1980	27.699322692883946
1981	27.870488406692203
1982	28.274928120786324
1983	28.697696523834832
1984	28.8948334004963
1985	30.56036406508386
1986	31.861703179373624
1987	32.59189825367733
1988	33.080353979165196
1989	34.43928870666593
1990	43.478869563154014
1991	44.156219537740135
1992	45.26011196333065
1993	45.706075143684984
1994	46.26348890061329
1995	45.28467408413233
1996	47.15414744359296
1997	46.722905518503175
1998	47.47744075343763
1999	48.04482930661474
2000	48.93448755399069
2001	49.31654061776901
2002	49.84273125382457
2003	50.6272841828307
2004	49.034696529667094
2005	49.100469731297174
2006	49.777485771515344
2007	49.358513604038016
2008	48.7668472715448
2009	48.83840536150172
2010	49.63931678757418
2011	50.21357851055533
2012	50.644263015577934
2013	50.82704456734615
2014	50.54593811309954