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	1.62256298681066
1971	1.7679135015209773
1972	1.839928313510327
1973	1.8659967093628775
1974	2.01282498606591
1975	2.1349241378805126
1976	2.084372602925453
1977	2.037787852773435
1978	2.18075709999755
1979	2.5643753074603275
1980	3.3618750824395027
1981	4.418382678167437
1982	4.691178975994608
1983	5.201936869641818
1984	5.268849798058713
1985	4.821139436818001
1986	5.116452231904278
1987	5.7782044672254225
1988	6.056054842465689
1989	6.48396731249831
1990	3.952936343814749
1991	3.8298180341185186
1992	4.241164845343771
1993	4.185802979959581
1994	3.826611393402942
1995	3.886403273794794
1996	3.5218034207134976
1997	3.855819895779559
1998	3.816591096435499
1999	4.051168524143901
2000	4.510181867282828
2001	4.819299147578569
2002	5.047545018814811
2003	5.543973401364289
2004	6.355345608693871
2005	7.403825679128663
2006	7.1645583905741566
2007	8.397700310969327
2008	8.903732617868899
2009	9.64545282245067
2010	11.12833946233845
2011	11.913463875031644
2012	13.288606307205134
2013	12.988392089629697
2014	13.694351167583937
2015	15.323759726354918