Year	% of total energy
1971	80.34401112914374
1972	79.9588170139596
1973	78.61912155227031
1974	77.89499272435411
1975	77.11441571327168
1976	76.23877837187123
1977	75.13760717379496
1978	74.30386048742939
1979	73.30574943470731
1980	72.09686319603625
1981	70.64074759705105
1982	69.45841335692442
1983	69.03148644446826
1984	69.85231556163089
1985	68.96180070439733
1986	68.89972488197765
1987	66.9536210155134
1988	66.58343890242446
1989	65.76242794809555
1990	46.39758960151423
1991	45.90576850131176
1992	46.23968169452578
1993	46.17976356000049
1994	47.431234678498996
1995	48.317641640583986
1996	47.6179968819183
1997	47.605649363810954
1998	47.09635984748353
1999	46.511222639673576
2000	46.72656637525745
2001	46.71927235826944
2002	46.829154937024484
2003	46.775524414209485
2004	46.514005844249624
2005	47.02742828664638
2006	47.01296958798
2007	46.85922851509952
2008	47.42737945653893
2009	49.46106414230562
2010	49.31050776656063
2011	48.822017720580384
2012	49.10577845247408
2013	50.035668194706986
2014	57.27602100857198