Year	% of total fuel combustion
1960	24.8062015503876
1961	23.705057891529556
1962	23.20561252023745
1963	27.057663873829473
1964	24.415467625899282
1965	22.396274343776458
1966	20.954128440366972
1967	23.225152129817445
1968	24.239573534023208
1969	23.603192702394526
1970	23.37798791699501
1971	16.00050497288515
1972	15.813090852888903
1973	15.404622454277687
1974	15.044919238467624
1975	15.304283535880968
1976	15.060118927035045
1977	15.174503496657039
1978	14.929804051221398
1979	14.888297628331577
1980	14.28622245218038
1981	14.542366736315847
1982	14.513874231036311
1983	14.769124802416046
1984	14.807373062437126
1985	15.201561484812462
1986	14.682403643665213
1987	14.494709148240572
1988	14.622318129742014
1989	14.25660881587042
1990	12.562230897504472
1991	12.139862475324879
1992	11.374665160874086
1993	11.586962268409826
1994	11.37418534705406
1995	11.445424561223323
1996	10.844587901488882
1997	11.202400955987052
1998	10.232207335882052
1999	10.692345670106116
2000	10.281385867358264
2001	10.04388835944535
2002	9.765348197073955
2003	9.413634443767027
2004	9.158513461614634
2005	8.719617548621992
2006	8.50859137620351
2007	8.263609343026484
2008	8.186591886950666
2009	7.832729867979937
2010	7.37162948127028
2011	7.239691884669209
2012	7.137563572913633
2013	7.048273083788488
2014	7.053495251253168