Year	% of total fuel combustion
1960	15.330154601936135
1961	14.922048997772828
1962	14.823847058311198
1963	14.983741228820811
1964	14.452644526445264
1965	13.878905170030412
1966	13.978125833619147
1967	13.554724726926178
1968	13.38610254973382
1969	12.38786151504356
1970	12.333459024635495
1971	10.466321243523316
1972	10.398481267099704
1973	10.217199364294542
1974	9.766803840877914
1975	9.97454480600548
1976	9.448616241748926
1977	9.335036506945753
1978	8.619347437140632
1979	8.027031037133954
1980	7.57856066812908
1981	7.223029548128157
1982	7.206925181364074
1983	7.294718451820993
1984	7.144927536231884
1985	6.779899471779196
1986	6.941239569431105
1987	7.239873009810708
1988	7.604825230724511
1989	8.429307144876411
1990	11.366136280653732
1991	11.752669820524446
1992	11.562933661889632
1993	11.045329809940034
1994	10.896937371498382
1995	10.897199407131254
1996	11.182361150612808
1997	11.409975889509845
1998	12.564973833305576
1999	12.434636843553754
2000	12.052694914180755
2001	12.419935984077187
2002	12.680997975559354
2003	12.68416687457435
2004	13.559809162499281
2005	13.713718797827529
2006	13.835837310174115
2007	14.392666645373534
2008	14.894045655431183
2009	15.220626216531487
2010	15.060943330659384
2011	14.678796880802077
2012	14.769146501547205
2013	15.399340124472145
2014	15.811600517529827