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	0.32117123274627385
1976	0.28511247955495367
1977	0.3185114867085181
1978	0.42003768223082644
1979	0.3582325607649798
1980	0.3526079973854097
1981	0.3348385199385453
1982	0.10759722102318015
1983	0.08999053691712877
1984	0.006186136828922411
1985	0.14129634952245507
1986	0.1708451192289405
1987	0.21209612448625462
1988	0.5544305921070684
1989	0.5730791615948573
1990	0.5557027923580901
1991	0.5236268133066928
1992	0.5333667669504533
1993	0.5327634685077285
1994	0.5393482824838971
1995	0.5211862510618511
1996	0.5111397155770422
1997	0.5332560506271934
1998	0.538742990372276
1999	0.5649305818125772
2000	0.5857732840880869
2001	0.6145097191826894
2002	0.6754489659172341
2003	0.6293479019470013
2004	0.7585132558474608
2005	1.032321573884819
2006	1.1453964539582795
2007	1.3621471683542292
2008	1.424976821325785
2009	1.6053829624276077
2010	1.362489301050938
2011	1.5746200750255734
2012	1.6175587437697363
2013	1.5127931152682397
2014	1.6406779743032733
2015	1.6127686825565943