Year	% of total fuel combustion
1960	22.59593451817846
1961	22.1830289444188
1962	23.36232756103389
1963	24.533964188387145
1964	22.700148167445498
1965	22.368011455609512
1966	21.863902002625764
1967	21.54367011564212
1968	21.603346844615434
1969	21.809148014757255
1970	22.942257357415908
1971	21.35517306561371
1972	21.684710448370954
1973	21.385081503852554
1974	20.14842016300023
1975	20.444114983124948
1976	20.103835139696592
1977	19.701193608083617
1978	19.82644448853961
1979	19.59086124753273
1980	18.83332494843286
1981	18.600625138793706
1982	18.376382502264995
1983	18.021873045730523
1984	19.11467826973207
1985	20.129574657103845
1986	20.391777612504185
1987	20.14649953339617
1988	19.37090976888203
1989	17.948899410014885
1990	14.296303194916302
1991	14.691797713970567
1992	13.997924500255998
1993	14.863298779230359
1994	14.767184921339819
1995	15.208889921400084
1996	16.02016727007295
1997	15.682887262947846
1998	15.34185507709515
1999	15.604020084302489
2000	14.99683311556017
2001	15.457442671463935
2002	14.838452711737428
2003	15.0111589192468
2004	14.930061086371683
2005	14.853387399952894
2006	14.65564813260945
2007	13.502171665256233
2008	14.900580743388005
2009	15.227588159850903
2010	15.285748379581703
2011	14.184784415017116
2012	14.505078988688433
2013	14.70130751917374
2014	14.085581108407307