Year	% of total electricity output
1990	16.399822192547518
1991	16.165476219867713
1992	15.938203447708071
1993	16.525746847735093
1994	15.831891249580874
1995	16.295091293863106
1996	16.299310144530033
1997	16.184490569280275
1998	15.545021211262382
1999	15.358015451330145
2000	15.131440360703172
2001	14.386033988494463
2002	14.606904569715596
2003	14.48478244088423
2004	14.648254394933412
2005	14.717390557196007
2006	15.057876529939271
2007	14.978836531300825
2008	15.851298012471965
2009	17.025179290854517
2010	17.211035190465424
2011	18.5436555674287
2012	19.552752223203996
2013	20.933076267497615
2014	21.72327645851676
2015	22.38785436299637