Year	% of total electricity output
1990	26.02858892943305
1991	25.51934093618784
1992	25.221915184364022
1993	25.259808679074762
1994	24.953712859529084
1995	24.015440065656108
1996	23.445283396923063
1997	22.68928183113195
1998	22.23826846872965
1999	21.55048621704459
2000	20.688272120064106
2001	19.75691669534879
2002	19.271320235544415
2003	19.121024586618248
2004	19.70715165482508
2005	20.23718994363256
2006	20.727432539576114
2007	19.503571969719367
2008	19.01642264100787
2009	18.26933622423902
2010	18.756402562796467
2011	19.105243979483006
2012	18.407208770803766
2013	19.06642076262428
2014	18.27134360206644
2015	18.10486154354886