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	13.922991283886477
1972	13.390807718443174
1973	10.242631443070339
1974	10.006519018975197
1975	9.540919023903607
1976	9.207121759070445
1977	8.900424484535248
1978	8.804672212513992
1979	7.478190621862953
1980	7.078057177682957
1981	8.649295191976963
1982	8.070707778606389
1983	8.124066222588494
1984	7.678958818750205
1985	7.718293636920405
1986	7.537707765412899
1987	7.469763737192645
1988	7.386609905712849
1989	7.3732922741212334
1990	5.212252315577029
1991	5.659871727340818
1992	6.154599504910882
1993	6.217256130446053
1994	6.327312950778744
1995	6.550914536790564
1996	7.059025808105804
1997	6.650707939357731
1998	6.199701197786555
1999	6.098083264488436
2000	5.899787709137523
2001	5.8521033878034086
2002	6.376364304544208
2003	6.878035530288166
2004	7.034621924905146
2005	7.5328448282319505
2006	7.28651580550946
2007	7.3639888519574
2008	7.557325275367814
2009	8.193446258426272
2010	8.123531179812469
2011	6.2312657465893615
2012	5.092864197807304
2013	6.704333239608899
2014	6.048788027003967
2015	6.35532845696064