Year	% of total fuel combustion
1960	1.789654735635096
1961	1.7721862366928882
1962	1.7111139992455626
1963	1.5932055538055208
1964	1.4406455772647573
1965	1.3889658842703974
1966	1.275006304110281
1967	1.1313531286459642
1968	1.1350007034143024
1969	1.0702888997789017
1970	1.086122787101526
1971	1.7598482360465324
1972	1.6254437215700894
1973	1.5928948480146568
1974	1.8193633548256083
1975	1.968089602704987
1976	1.7590479882037475
1977	1.5016817214343743
1978	1.5259443399527188
1979	1.7553679908445576
1980	1.2879950569053837
1981	1.3110336723530114
1982	1.2643460780834646
1983	1.5408188596228407
1984	1.416215773077553
1985	1.54193819205862
1986	1.5035645913828815
1987	1.4130298613417223
1988	1.3967509121212474
1989	1.3630700970067449
1990	1.4105787662510516
1991	1.3794501897395786
1992	1.0515215140085699
1993	0.9919501718053232
1994	0.9919770332965918
1995	0.9909291590683955
1996	0.9909356006042932
1997	0.9749820424920593
1998	0.8992165543987884
1999	0.8606057950153644
2000	0.8816638279148077
2001	0.922692410237454
2002	0.9616211034345971
2003	0.864977838401826
2004	1.0310771513496384
2005	1.0833126247524993
2006	1.1911952437077398
2007	1.1130869418945555
2008	1.114713591775994
2009	1.095226092297206
2010	1.112057075720684
2011	1.0821467536467422
2012	1.115570760265424
2013	1.1595941155242324
2014	1.1343550264264062