Year	% of total electricity output
1990	16.100045571447517
1991	16.35667711127399
1992	17.297095240116043
1993	18.34282050572941
1994	18.989168823759655
1995	18.90203709967295
1996	17.851949919358685
1997	18.30907534265109
1998	18.857732704344702
1999	18.902786880465897
2000	19.021780302592006
2001	18.976725052999612
2002	17.93036322236145
2003	17.08249372535864
2004	18.436078314014928
2005	18.611465428063607
2006	18.481535059721494
2007	18.948343484708108
2008	19.63669977419487
2009	21.31451441099234
2010	22.285701991231363
2011	22.116947341020467
2012	24.230534428931932
2013	26.423832003333768
2014	27.115884798557822
2015	28.020176437837005