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	16.804219940521417
1972	16.961955831568428
1973	17.106562562686133
1974	17.276936730200106
1975	16.919097630022875
1976	16.65173314218422
1977	16.25044993053965
1978	16.045923957515626
1979	15.9887195577469
1980	16.072775635617162
1981	16.362136221455167
1982	15.9909255577422
1983	15.65292831046323
1984	15.215013648349917
1985	15.25713421283763
1986	15.216429754646457
1987	14.963279918590533
1988	14.91928455743105
1989	15.239761365163936
1990	13.909197177526602
1991	14.16434103041534
1992	14.306457046603029
1993	14.232570122770856
1994	14.213377949910564
1995	14.124181086305347
1996	15.115665405928402
1997	15.006608104880447
1998	15.251148371247812
1999	15.63300239643958
2000	16.111822341523936
2001	16.05592035585681
2002	16.03333992124907
2003	15.596811032409288
2004	15.618562700265894
2005	15.159115502198894
2006	14.759704780158483
2007	14.743477687924075
2008	15.139236636633889
2009	15.032079956565921
2010	14.92076409165377
2011	14.748424409521698
2012	15.210649030303895
2013	15.356946397573623
2014	15.497373001216593