Year	% of total fuel combustion
1960	24.543659394114524
1961	22.69394951744617
1962	22.666898924356573
1963	22.3087455074448
1964	21.992619926199257
1965	21.351554168806032
1966	19.458099919972565
1967	18.510373139799135
1968	17.38582235920426
1969	18.913754574602457
1970	20.45940170940171
1971	15.57511100755882
1972	15.487484477034458
1973	15.133979917936557
1974	14.892238818555702
1975	15.13690361635495
1976	14.767984003220475
1977	14.712365978765089
1978	14.481377126756701
1979	14.349423163636764
1980	13.962886866553939
1981	14.256403611075115
1982	14.482717137454788
1983	14.410104538436228
1984	14.4481258960552
1985	15.039080760672412
1986	14.640835618836435
1987	14.637244544748201
1988	14.73890138078269
1989	14.204864230758671
1990	12.55559245591504
1991	12.290300477342333
1992	11.592291970802917
1993	11.812349359011677
1994	11.49721074003344
1995	11.209435545745611
1996	10.574508424852898
1997	10.860724541639055
1998	9.863066872227181
1999	10.336592430852399
2000	9.918528681424243
2001	9.70647098065377
2002	9.474584970074563
2003	9.164225232736754
2004	8.96954014277767
2005	8.566288501697978
2006	8.39420041111724
2007	8.17156392286403
2008	8.032761907341634
2009	7.761020520707066
2010	7.344337574148466
2011	7.1567445151502325
2012	7.051444931961833
2013	7.012990742039401
2014	6.992237844012042