Year	% of total fuel combustion
1971	10.793237971391415
1972	5.909090909090908
1973	3.138461538461538
1974	7.322654462242564
1975	4.662643993417444
1976	5.888708806050782
1977	4.07040704070407
1978	4.686648501362397
1979	4.16883793642522
1980	2.9426189308484556
1981	2.871939736346516
1982	3.038936372269705
1983	1.631963984243108
1984	2.6358257127487894
1985	3.213296398891968
1986	3.4679089026915113
1987	3.063666826232647
1988	3.9040451552210724
1989	3.575129533678758
1990	3.552769070010448
1991	4.695089044792231
1992	5.5297157622738995
1993	7.29270729270729
1994	8.714703018500487
1995	7.25321888412017
1996	7.089988313206078
1997	6.141732283464568
1998	3.5641130684145845
1999	5.139664804469275
2000	4.2819249715801435
2001	3.6169338265515836
2002	3.5266457680250793
2003	3.1363088057901085
2004	3.7899860917941592
2005	3.459119496855345
2006	3.2119914346895073
2007	2.7499191200258823
2008	2.187499999999999
2009	2.1225789334040854
2010	1.0221465076660992
2011	1.0628674807779281
2012	1.1818181818181823
2013	1.2711864406779663
2014	0.8369951872776735