Year	% of total energy
1971	63.088128123511154
1972	63.07745016418399
1973	62.7301668349338
1974	61.742610094718685
1975	61.001038629019
1976	60.00115287812646
1977	59.67779674647764
1978	60.2218539266104
1979	58.90836665133071
1980	58.225430396795744
1981	56.18064361159003
1982	54.829908264274195
1983	53.83430727019686
1984	52.39936653847058
1985	50.474824968525986
1986	49.420398067994476
1987	48.257018562949234
1988	46.394043678993874
1989	44.913479206388544
1990	42.6257957592865
1991	41.47023877972802
1992	40.55393697828949
1993	39.810007897124606
1994	38.53504563088102
1995	36.7944870631686
1996	36.03641336691225
1997	35.01139023587658
1998	34.532092428552886
1999	33.10407454884833
2000	32.7662807986021
2001	32.68359705988139
2002	32.108782833124614
2003	31.723565584183394
2004	30.610393019808836
2005	29.925253784002614
2006	28.884901200804368
2007	27.769881805284115
2008	26.886405110780686
2009	24.774845612620027
2010	24.051799631087565
2011	23.427370410400496
2012	22.632883612745097
2013	22.42388316927727
2014	21.373920432278393