Year	% of total energy
1971	77.91060565088208
1972	77.22379368938223
1973	77.99713076761559
1974	77.93978336443848
1975	78.92310849003529
1976	78.08471695997075
1977	77.20480207035224
1978	77.78179592704511
1979	77.9289989779977
1980	78.01860423111403
1981	78.80549845231279
1982	80.36322093645704
1983	82.0098948819747
1984	80.47460084066672
1985	80.03206600117629
1986	76.18523422985798
1987	75.81218655001713
1988	76.58369000423615
1989	76.45078227647384
1990	51.33991538210058
1991	52.085262104108565
1992	52.424936398400376
1993	52.76999755565288
1994	53.712299244397165
1995	52.72564344012765
1996	52.244067321948094
1997	52.95742374491357
1998	52.32924843861322
1999	52.47901821357248
2000	51.971143286488186
2001	52.580942979947885
2002	53.239047793775796
2003	53.46753228060077
2004	52.19493397222017
2005	51.72374192535637
2006	50.922183979719925
2007	51.163152394675606
2008	50.73599002161101
2009	49.229315992491834
2010	48.399680977281676
2011	48.700936864657926
2012	49.40259810664835
2013	47.96785602098524
2014	44.4500799384039