Year	% of total energy
1971	57.181319182244
1972	56.398855810043244
1973	54.158715148263234
1974	53.461010283584045
1975	54.21127220600408
1976	53.02067848716213
1977	48.980255765177475
1978	51.28911707658569
1979	59.96611920227021
1980	56.28316888840528
1981	56.10261010684429
1982	57.723152119638875
1983	54.62120269979989
1984	51.89337504092738
1985	52.28026319332116
1986	49.17999428372602
1987	50.07551042587265
1988	52.963317553838586
1989	50.448211452247584
1990	46.85675796816202
1991	46.16098917998342
1992	43.38307193550023
1993	44.47175336867683
1994	44.28372141841698
1995	43.961782171293095
1996	44.49380974714351
1997	43.77472583926038
1998	43.31353481120484
1999	43.9646803193183
2000	42.75102378812334
2001	40.21059524752116
2002	40.524113365198666
2003	36.52492023078111
2004	35.793832167156644
2005	35.21942719789533
2006	34.316628544255394
2007	34.20066502789543
2008	33.89379876218894
2009	33.70790667493196
2010	33.994402819343684
2011	33.09538282109818
2012	31.958581198521042
2013	30.078275079947918
2014	29.405430398952433