Year	% of total energy
1971	43.87247310231621
1972	42.85339812911792
1973	42.09624332952237
1974	41.92206251570102
1975	39.21890640744624
1976	38.594878036163806
1977	36.13848273853366
1978	33.94209956486632
1979	33.711997490988736
1980	34.00801392714522
1981	34.536074606960945
1982	34.02282044417017
1983	32.840136176943766
1984	31.5530457319569
1985	31.105587114699038
1986	30.293707369285958
1987	29.252138934836147
1988	28.16396336397633
1989	27.93506922711429
1990	25.8067625862377
1991	26.291863368938763
1992	25.568631481541964
1993	24.166622202368718
1994	23.114534944596144
1995	21.579119758472377
1996	20.870072183425908
1997	20.763195223181217
1998	20.61548361475219
1999	20.12260825206175
2000	19.196898205013248
2001	17.955106110588197
2002	16.781827659079877
2003	14.72954711970059
2004	12.700377776297145
2005	11.362509035271922
2006	10.47423238244181
2007	9.266781334394244
2008	8.533686449577067
2009	7.798633465654863
2010	6.802424792043705
2011	6.185295801544855
2012	5.876255995950306
2013	5.486704616919985
2014	5.061653719967917