Year	% of total energy
1960	7.0967239889227995
1961	6.164539177629201
1962	5.7693728825715755
1963	5.774852935502492
1964	4.491496978605551
1965	4.470220279936594
1966	4.948052369390188
1967	4.545413151382019
1968	3.9443622681706243
1969	3.686078900574769
1970	3.7086317243583826
1971	3.5767092799215265
1972	3.256517856345545
1973	3.3366117387090117
1974	3.3778217494814253
1975	3.509570002565996
1976	3.330844034567167
1977	3.45058485481737
1978	3.8460517059279455
1979	4.368069695875581
1980	4.910961945955293
1981	5.732519516000275
1982	6.603159396946218
1983	6.710340362476668
1984	7.557437459585375
1985	8.07089849352527
1986	9.24706276174892
1987	9.540527114344505
1988	13.597020193667667
1989	11.605980425789356
1990	8.844692311065817
1991	8.995549252868539
1992	9.078514648627188
1993	9.033106768282996
1994	8.320568696059631
1995	8.767086415965727
1996	8.67235589962743
1997	8.646884053406453
1998	8.187317736312865
1999	9.425745039390348
2000	8.98495653967744
2001	9.162860180482653
2002	8.479619060497123
2003	8.347725158843021
2004	8.239079457919113
2005	9.076930076472204
2006	9.962738211446913
2007	11.031658502291446
2008	11.696340251407998
2009	12.716506938230884
2010	13.405217684933934
2011	13.314020994501293
2012	13.50814220371436
2013	14.548503100987297
2014	13.786311763239075
2015	14.142504905792826