Year	% of total electricity output
1990	19.486412595752892
1991	21.022759516458983
1992	20.03376976564509
1993	19.07230603739533
1994	18.51157217884452
1995	18.65890565386968
1996	18.05836275895648
1997	17.82783219414799
1998	18.890325518092435
1999	19.894845638739987
2000	20.610200388008213
2001	21.959522459732092
2002	22.025186372303487
2003	20.646439673437047
2004	20.918417268381297
2005	21.32164342039779
2006	21.5857274746035
2007	20.664487829378007
2008	21.462766837884164
2009	22.70744037781432
2010	23.7507065867889
2011	23.822171020559573
2012	24.110609186646375
2013	24.783002712179414
2014	26.601513338153914
2015	26.637447426755347