Year	% of total energy use
1960	0.8061091873266525
1961	1.0026897227851863
1962	0.8154736857379168
1963	1.4806813793121174
1964	1.105815086661768
1965	1.409250236588663
1966	1.373220706346643
1967	1.3493500040400082
1968	1.7038788894443258
1969	1.7495392460005037
1970	1.5558481892071114
1971	1.2637140587611921
1972	1.3151126439421403
1973	1.266378981438272
1974	1.7999111206009826
1975	3.034400164139949
1976	4.483556960746507
1977	4.681821007301668
1978	4.643901664964307
1979	5.057091458021599
1980	5.111812874290879
1981	6.528535236010278
1982	7.029011762678635
1983	7.062743084298104
1984	7.363914637288195
1985	6.977000034039044
1986	6.644932320367129
1987	7.128778918523592
1988	9.266665159679647
1989	7.583021838988259
1990	4.928106600118773
1991	5.008800363891301
1992	5.454940982275278
1993	5.971398171021635
1994	6.131002370303038
1995	6.4104096502002745
1996	6.972382438263364
1997	7.17615654858712
1998	7.14212147745089
1999	7.399462888684407
2000	7.647088464589599
2001	7.801318413134595
2002	7.914385873742101
2003	7.8151501688747915
2004	7.921807771232639
2005	8.073729561937345
2006	8.034121558461598
2007	7.898802629001828
2008	7.773586458085659
2009	8.310769854914376
2010	8.229050799624927
2011	7.916616292274438
2012	7.954504994845529
2013	7.981787489252366
2014	8.56536893681134
2015	6.654300586536417