Year	% of total electricity output
1990	66.9471541400594
1991	66.68537597604673
1992	65.21731009823623
1993	66.73146572904027
1994	65.48588667679171
1995	60.956307255091524
1996	60.32838992984338
1997	57.58471790458319
1998	56.17063159625093
1999	57.404099415852
2000	56.50202678296099
2001	55.4548342363456
2002	53.15228322822512
2003	52.44385690231647
2004	51.70881966723299
2005	51.03973472224401
2006	49.558610444646476
2007	49.12069587618632
2008	47.43433112622259
2009	48.009617673234494
2010	48.13127746354319
2011	49.95250616516296
2012	50.26669516189676
2013	51.94483467184949
2014	52.012854803748546
2015	50.580593342337295