Year	% of total fuel combustion
1971	0.5934718100890213
1972	0.7936507936507936
1973	0.7263922518159813
1974	0.7263922518159813
1975	0.6928406466512695
1976	0.6960556844547557
1977	1.0526315789473688
1978	1.101928374655646
1979	1.2345679012345672
1980	3.0487804878048776
1981	2.702702702702703
1982	2.816901408450704
1983	2.2058823529411753
1984	2.9197080291970807
1985	2.5925925925925917
1986	2.5179856115107917
1987	4.059040590405905
1988	3.3112582781456936
1989	5.466237942122186
1990	4.687500000000001
1991	1.8315018315018305
1992	2.214022140221402
1993	2.109704641350211
1994	1.9704433497536953
1995	6.999999999999999
1996	7.4074074074074066
1997	2.3474178403755865
1998	2.463054187192118
1999	3.0487804878048785
2000	3.03030303030303
2001	2.8571428571428563
2002	2.7322404371584708
2003	2.577319587628867
2004	2.0512820512820515
2005	2.3584905660377364
2006	6.122448979591837
2007	8.27067669172932
2008	8.609271523178808
2009	6.369426751592357
2010	7.317073170731709
2011	6.0606060606060606
2012	5.147058823529412
2013	8.421052631578947
2014	5.329153605015673