Year	% of total fuel combustion
1960	13.675213675213676
1961	16.521739130434785
1962	16.12903225806452
1963	17.322834645669293
1964	18.6046511627907
1965	20.000000000000004
1966	21.333333333333332
1967	18.30985915492958
1968	18.120805369127517
1969	15.789473684210526
1970	15.151515151515154
1971	23.75745526838966
1972	23.992994746059548
1973	29.048295454545453
1974	30.83391730903994
1975	33.23335332933413
1976	32.46753246753247
1977	29.29562433297759
1978	28.62964849719816
1979	31.78571428571428
1980	26.425301706200585
1981	29.48579647608774
1982	28.551865799383773
1983	28.781302170283805
1984	21.577946768060833
1985	20.112254443405057
1986	19.642342082492064
1987	19.175374188082465
1988	16.497326203208555
1989	14.692188308329024
1990	12.918215613382898
1991	12.335393711367912
1992	11.994261119081779
1993	12.553855296389838
1994	12.184750733137829
1995	12.623216124760926
1996	13.162705667276052
1997	12.45056593481522
1998	12.523191094619664
1999	11.6701244813278
2000	13.175454664398796
2001	13.266851805099723
2002	15.166726425242022
2003	12.958626073380174
2004	14.199199740456365
2005	12.990876636255456
2006	13.96071265417999
2007	15.039046099588546
2008	14.611908988220106
2009	12.257908327953519
2010	11.353711790393014
2011	9.830701379997155
2012	12.266433660438233
2013	12.744402142350133
2014	13.053152039555007