Year	% of total fuel combustion
1971	4.953560371517027
1972	5.325443786982246
1973	5.084745762711862
1974	5.397727272727272
1975	5.202312138728322
1976	4.534005037783373
1977	5.048076923076924
1978	6.024096385542168
1979	5.853658536585365
1980	4.78359908883827
1981	5.36130536130536
1982	3.4398034398034385
1983	3.9999999999999996
1984	3.1390134529147997
1985	3.26797385620915
1986	2.8790786948176588
1987	4.797047970479705
1988	4.089219330855019
1989	5.45774647887324
1990	7.065217391304349
1991	3.3898305084745757
1992	5.8052434456928825
1993	6.8181818181818175
1994	5.313092979127135
1995	4.537521815008725
1996	5.136436597110755
1997	4.643449419568823
1998	5.471124620060792
1999	4.202898550724639
2000	3.737113402061856
2001	3.9548022598870047
2002	3.660322108345536
2003	3.4129692832764515
2004	2.9761904761904776
2005	1.7379679144385027
2006	1.6587677725118484
2007	2.6252983293556094
2008	1.7006802721088436
2009	1.1505273250239683
2010	1.4272970561998208
2011	1.3250883392226152
2012	1.2560386473429963
2013	1.2820512820512833
2014	1.6194331983805665