Year	% of total fuel combustion
1971	4.190919674039581
1972	4.253112033195019
1973	4.27661510464058
1974	4.187604690117254
1975	4.501845018450186
1976	4.39146800501882
1977	4.176072234762978
1978	3.8104089219330874
1979	3.448275862068967
1980	3.461954561846376
1981	3.238866396761133
1982	2.904238618524333
1983	2.70205643232903
1984	2.7696078431372553
1985	0.19020446980504097
1986	0.21150592216581943
1987	0.21222410865874264
1988	0.2018978396931143
1989	0
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	4.162694629806163
2010	3.7276809021614286
2011	3.878170600332973
2012	3.1896629619589763
2013	4.048120828942746
2014	2.3672008460099243