Year	% of total electricity output
1990	99.791959608917
1991	99.801018423885
1992	99.8172689391352
1993	99.8037053742963
1994	99.6429938659046
1995	99.6621455800789
1996	99.4995128846778
1997	99.5773526164317
1998	99.6160816277452
1999	99.5608691030118
2000	99.7151097108293
2001	99.5203046312857
2002	99.5830773955774
2003	99.3990756452203
2004	99.350631658296
2005	99.4717476046486
2006	99.3161307353451
2007	99.134536264253
2008	99.4029618193021
2009	96.5704425900335
2010	95.7326473977182
2011	96.4944211442589
2012	97.9549112135512
2013	97.7022692526755
2014	97.6555308512597
2015	97.709870624366