Year	% of total energy
1960	10.40356228935082
1961	10.10935640855926
1962	9.532017826153963
1963	9.19668158294725
1964	8.928718002077703
1965	8.592928612968054
1966	8.404883194267644
1967	8.191801161829234
1968	7.836641706833815
1969	7.4364272876630135
1970	6.946360305561152
1971	5.384504498453503
1972	5.537900826187623
1973	5.180617063778938
1974	5.033819886168194
1975	4.871538840787459
1976	4.620170518839959
1977	4.456974530431636
1978	4.236311785814965
1979	4.161740016215958
1980	4.0908529001069995
1981	4.47763812288175
1982	4.3946400818115245
1983	4.436818516212039
1984	4.492494120035397
1985	4.40123889955584
1986	4.55311335471671
1987	4.174999835642571
1988	4.147220374633219
1989	4.15335560152099
1990	1.4449445821890072
1991	1.4380674513198068
1992	1.5417943625144084
1993	1.8536536472812342
1994	1.7590095921040132
1995	1.7650122187149522
1996	1.8695540496207599
1997	1.9363115518010987
1998	1.8992456408058471
1999	1.9486792911793787
2000	1.8475667047527489
2001	1.78257075382098
2002	1.744444708195955
2003	1.7236909304737627
2004	1.7017097499986988
2005	1.6893711999212961
2006	1.644255293454443
2007	1.7110295225822825
2008	1.733000922976581
2009	1.872681599577477
2010	1.840054244804698
2011	1.717979732539707
2012	1.753632736347193
2013	1.800908759458432
2014	1.9063218559182824
2015	4.034478965561685