Year	% of total energy
1971	8.94510292848318
1972	8.629189916272919
1973	4.18755751940055
1974	2.3082130419846556
1975	1.754684539028933
1976	1.25733848670698
1977	1.0951484865195729
1978	1.0991662476276987
1979	0.9866988127455175
1980	0.6971251090994499
1981	0.6688597756872704
1982	0.5708854163684359
1983	0.49198091439328795
1984	0.3847995078706585
1985	0.32694792679553436
1986	0.32646604657284123
1987	0.2736267753202847
1988	0.27552419264220057
1989	0.19102720508683319
1990	0.13000264058815628
1991	0.07824978581169557
1992	0.03867274381212286
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	0
2010	0
2011	0
2012	0
2013	0
2014	0