Year	% of total energy
1971	37.7627884317383
1972	38.04915153715609
1973	36.88294592878261
1974	35.320570986166615
1975	33.38475101503487
1976	32.995320183647806
1977	32.189856333725956
1978	33.20184573607229
1979	33.089833831773504
1980	30.506315913458405
1981	30.58925290709454
1982	31.190927898846
1983	34.26057265488203
1984	33.799293975781616
1985	33.28818561364919
1986	30.41536056993177
1987	27.81267571300445
1988	26.545692680788047
1989	27.450075465062536
1990	26.454789087825326
1991	25.911530574533188
1992	25.711046870172797
1993	23.159297238934652
1994	21.92298152316459
1995	20.271540869453624
1996	19.324125805926904
1997	19.871584277549108
1998	18.45611156462632
1999	17.19072375691284
2000	17.246173541942067
2001	18.068449076401635
2002	17.936786689551592
2003	18.112498808843867
2004	17.15305147942621
2005	15.361904085557473
2006	16.52964218666689
2007	16.49891426782017
2008	11.324204917477802
2009	14.685553320343331
2010	15.53025051287841
2011	14.96835761038621
2012	13.316299790197473
2013	12.88353131652708
2014	11.163441683016918