Year	% of total energy
1971	45.437161303099685
1972	47.44521154490977
1973	35.20849397289606
1974	33.02600755275297
1975	40.991354848546216
1976	43.72820831068696
1977	40.938665849889155
1978	36.801595925847835
1979	42.45619383837177
1980	43.024926208177355
1981	39.170901723337295
1982	38.90151028318125
1983	38.63847125393389
1984	42.46288876671199
1985	48.50801639236973
1986	49.4629099924424
1987	53.0918899885757
1988	51.16896547930335
1989	56.032332479839454
1990	62.70256042593353
1991	62.6577086765851
1992	60.37922526867909
1993	58.38515593178574
1994	65.89705966039168
1995	61.821722983275386
1996	60.37977775566012
1997	60.48335243074712
1998	58.25027199263781
1999	61.23228255337752
2000	62.54852576686575
2001	59.72460797622298
2002	67.49009135798582
2003	72.73077704878665
2004	75.87712001495342
2005	77.11220580313653
2006	78.71935127356421
2007	79.80126604916555
2008	80.92027780880984
2009	81.56154204741924
2010	79.36801243274874
2011	71.6686892248986
2012	66.49955102196138
2013	75.54789832166034
2014	73.66032088834106