Year	% of total energy
1971	0.019991595647349883
1972	0.023533051779273093
1973	0.020337727950881967
1974	0.012034973088119726
1975	0.011107411174922338
1976	0.021283003161568486
1977	0.012953540116215535
1978	0.015720831753199452
1979	0.013109327021138177
1980	0.004729834794684013
1981	0.01043293020402784
1982	0.017067679084605446
1983	0.015610222241761795
1984	0.01770504463369112
1985	0.006398713421585137
1986	0.019214033296126275
1987	0.016073646579111783
1988	0.014040443666568663
1989	0.019477828798408797
1990	0.021115599823455105
1991	0.018139512220696607
1992	0.010519094021058493
1993	0.0073692466797912306
1994	0.015251921615976324
1995	0.012356453411029023
1996	0.004646331278710829
1997	0.0044850627471754705
1998	0.004879767468093598
1999	0.004793242839700838
2000	0.004584245890529107
2001	0.0051986450869468915
2002	0.004693883599111384
2003	0.004638729328562495
2004	0.004378871954505407
2005	0.00428075264836074
2006	0.004404414795104577
2007	0.004262361103754977
2008	0.0038207442970871757
2009	0.003589108081318207
2010	0.0032244484724023056
2011	0.0037710027928999955
2012	0.003352653676046247
2013	0.003495139580951444
2014	0.0031568314816846164