Year	% of total fuel combustion
1971	28.438605356240526
1972	28.14391554888383
1973	29.424729997795904
1974	28.322365609776938
1975	27.198063799396923
1976	28.591460939518058
1977	28.783285239434562
1978	30.409037787300353
1979	31.089017696057734
1980	30.956081691668174
1981	30.772657186911086
1982	27.910262595630297
1983	25.088849009465502
1984	23.8040149710786
1985	24.14228303829419
1986	23.638497652582156
1987	22.531087675114115
1988	23.306605098124862
1989	21.864427631174262
1990	21.744009705793147
1991	19.99029891469108
1992	18.06001019154102
1993	15.445945141905161
1994	15.10829842231928
1995	14.623753657358751
1996	15.308232221557212
1997	15.37532133676093
1998	15.701665825340735
1999	14.73114940744191
2000	14.267705418147898
2001	11.90589515196845
2002	12.340724170449809
2003	13.061343678952088
2004	13.327330031517336
2005	13.938238212916657
2006	13.413078766329136
2007	11.979021369190425
2008	11.204036494332321
2009	14.495578415448477
2010	12.736595773969306
2011	12.573325764222188
2012	12.056258141107026
2013	12.504354435190171
2014	12.96793289064058