Year	% of total electricity output
1990	64.20998651289582
1991	64.35620343691178
1992	64.57804905915103
1993	65.91075916658731
1994	64.85376095731105
1995	64.63156295777186
1996	64.42546273263606
1997	63.3964806581223
1998	61.23470597066909
1999	60.19141783130679
2000	60.25533661044119
2001	56.9290139149925
2002	57.4690688781733
2003	56.437345790042684
2004	56.692787700447084
2005	57.586393744441494
2006	58.00492717725448
2007	57.47090951240989
2008	56.732652699399104
2009	57.22911907506707
2010	56.4046214332476
2011	57.45282608695003
2012	54.88542744973293
2013	53.233137421236925
2014	53.062840386723664
2015	51.704748488006416