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	10.59227389937165
1972	9.853010213223437
1973	7.978615944253143
1974	8.148642501114907
1975	8.042120800535288
1976	7.921112876794854
1977	7.450157988039098
1978	7.1912034856343
1979	6.230324391254965
1980	6.033710729828397
1981	7.13906103576427
1982	6.923984965254649
1983	6.955950883094298
1984	6.694323333903682
1985	6.7046929539931535
1986	6.625763135297958
1987	6.698360912737164
1988	6.524493612945282
1989	6.61993519721626
1990	4.4588915433651275
1991	4.826949932158014
1992	5.110514183628522
1993	5.210033278769393
1994	5.30501274048108
1995	5.497950823658421
1996	5.767819424364081
1997	5.5857157258431664
1998	5.104160837937346
1999	4.912785037444558
2000	4.896991206893119
2001	4.7650111507969575
2002	5.178117641489646
2003	5.459820843382241
2004	5.587388977230986
2005	5.83296144389316
2006	5.62267147454696
2007	5.694956702229062
2008	5.960881642146872
2009	6.441118088149598
2010	6.383741377065293
2011	5.040108456399926
2012	4.306120009232079
2013	5.595729507573039
2014	5.1309377350015355
2015	6.35532845696064