Year	% of total fuel combustion
1971	7.688611244593946
1972	8.601087493821058
1973	8.986175115207375
1974	8.535031847133757
1975	10.463192721257236
1976	9.31157978511739
1977	8.739985433357612
1978	8.249158249158251
1979	10.040431266846364
1980	9.61286089238845
1981	7.276918011195257
1982	7.70239265814487
1983	6.598373003916843
1984	7.652324574068725
1985	8.082064034815046
1986	8.70229007633588
1987	8.817577334489735
1988	10.079430293070391
1989	10.545839957604663
1990	9.149560117302052
1991	8.361581920903953
1992	8.949599623174752
1993	8.303616912888435
1994	8.514664143803216
1995	8.110516934046345
1996	9.549180327868854
1997	9.435392194012884
1998	8.138195777351248
1999	7.921160282632949
2000	7.937088514996342
2001	7.180650037792895
2002	6.497622820919177
2003	9.918367346938775
2004	9.702725020644099
2005	9.500998003992017
2006	7.7437106918239005
2007	8.247814519194224
2008	7.970160973694543
2009	9.37606546198432
2010	10.312117503059977
2011	9.942895532415182
2012	10.222804718217562
2013	10.503059143439836
2014	10.831918505942276