Year	% of total fuel combustion
1960	34.916433612997736
1961	34.01566680635698
1962	32.37769241117471
1963	31.40217542881049
1964	32.182903546747696
1965	33.07476339862389
1966	32.310686992882324
1967	31.79659851821677
1968	31.23040425354363
1969	31.54613190652015
1970	30.189935310888796
1971	29.005140263333523
1972	28.036079874195174
1973	27.780456989354455
1974	28.333678529221853
1975	26.405852308638387
1976	25.316053239222796
1977	25.393434249252053
1978	24.44394008170676
1979	24.25492393192603
1980	23.012363400629756
1981	22.446336346029696
1982	21.40098982977103
1983	21.58427156522475
1984	21.560230634749864
1985	21.437406446148614
1986	20.114720047286635
1987	20.067997738910137
1988	20.182252455540386
1989	20.106612483455635
1990	18.688431979474384
1991	17.52776079175219
1992	17.038711386977365
1993	16.556191068876995
1994	16.926307845019238
1995	16.612752671559157
1996	15.995568354594488
1997	16.372534598121103
1998	15.8708409509977
1999	15.715271615892734
2000	15.913132025222263
2001	15.509133763202719
2002	15.105097960969097
2003	15.253180484763341
2004	14.61292434302815
2005	14.17061077304485
2006	13.789973678637342
2007	14.016273892684426
2008	13.886370386581419
2009	12.62920305446568
2010	13.270750542370518
2011	13.481291583784897
2012	13.25835866261398
2013	13.392857142857142
2014	13.574607745965253