Year	% of total fuel combustion
1971	11.210632765096792
1972	12.103424178895878
1973	13.14850398023607
1974	13.817175974710223
1975	14.514692787177205
1976	14.104989359186568
1977	14.523516925483184
1978	14.13960354280894
1979	13.75036884036589
1980	13.440014799741004
1981	13.511813853202767
1982	13.316173316173316
1983	13.22327692942633
1984	13.232574965833264
1985	13.22722707254887
1986	13.268277327457307
1987	14.000164514271612
1988	14.130610922054773
1989	15.553925165077034
1990	13.840623127621331
1991	13.535462912831619
1992	14.135215301217144
1993	12.829936518543269
1994	14.734270006108737
1995	14.898065865133297
1996	16.969606674612635
1997	17.05318491032777
1998	14.587525150905433
1999	16.163793103448278
2000	16.552315608919383
2001	16.66436177568801
2002	16.664253655711597
2003	16.517793846590102
2004	16.493272298515745
2005	16.24850657108722
2006	15.98066117862276
2007	16.311047889995255
2008	16.226200625177608
2009	15.939333237945345
2010	15.850495804729217
2011	16.229116945107396
2012	15.872340425531913
2013	16.23571858087793
2014	16.21693121693122