Year	% of total energy
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0.46550585463132554
1978	0.4333764601995952
1979	0.4820294356287004
1980	0.589699668964688
1981	0.6740695495905163
1982	0.6956773279471814
1983	0.7397037141862826
1984	0.7744787104235688
1985	0.7575628873901129
1986	0.5820921530625683
1987	0.821434586776635
1988	0.8895987123399984
1989	0.8487094093843291
1990	0
1991	0
1992	0.42404972859220613
1993	0.41817592438245543
1994	0.4332637902241535
1995	0.48919813175414517
1996	0.4822233555394637
1997	0.4955821344619252
1998	0.5132099159499232
1999	0.49315112283225443
2000	0.45398587330760937
2001	0.46732523262029346
2002	0.42832317692796873
2003	0.4368999681965145
2004	0.4625968935465073
2005	0.9105226149237317
2006	0.9284704243997867
2007	2.1383213314118863
2008	2.1906158872037804
2009	2.158427257819335
2010	2.1133772267393915
2011	2.084373995004326
2012	2.2224695407342225
2013	2.5636326203106266
2014	3.5599487708031834
2015	4.000334638249135