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	34.80597423384917
1972	34.04043921317845
1973	32.87421084518591
1974	32.28993503504829
1975	30.965209180605218
1976	30.019091918931768
1977	28.70144509849752
1978	27.390625022100572
1979	26.942747870450123
1980	26.721131244693687
1981	26.816590321591576
1982	26.21112558618068
1983	26.026393139610438
1984	25.513714595993434
1985	25.025937636622142
1986	24.476236086429576
1987	23.863399663013958
1988	23.219334600942812
1989	23.029009830567183
1990	13.816315795273589
1991	13.974145037465659
1992	14.322832943132173
1993	14.38578818007863
1994	14.504617086280312
1995	14.090137179546488
1996	13.938598825888315
1997	13.883720771624803
1998	13.911402720312436
1999	13.759755771286482
2000	13.367997530976092
2001	12.876610456635243
2002	12.526636617046494
2003	11.741916155633938
2004	10.906282606614596
2005	10.302143112142833
2006	9.8369688537347
2007	9.296482747002647
2008	8.905774263141387
2009	8.616122870073127
2010	8.037316360847214
2011	7.572221832350833
2012	7.332482114143433
2013	7.171588569699769
2014	6.986454193385873
2015	4.504159279122867