Year	% of total electricity output
1990	24.658460094135506
1991	24.666859902886
1992	25.05844273263926
1993	26.43249775324368
1994	27.09773254223876
1995	27.81668920951809
1996	26.916043044028697
1997	26.763241538162767
1998	27.019154698531896
1999	26.229495300393317
2000	25.745120296784446
2001	25.30065771216551
2002	24.716573030821372
2003	22.94609175177286
2004	23.65228287981544
2005	23.289080253746462
2006	22.623889632083785
2007	21.81297467421492
2008	22.60195354054705
2009	23.033728044988266
2010	23.328612230468767
2011	22.115883333424232
2012	23.62268684623474
2013	23.694263197111262
2014	24.669619665000035
2015	25.54383731079981