Year	% of total electricity output
1990	24.4892939617124
1991	22.8074022101386
1992	20.7526521363897
1993	19.5588133409081
1994	21.21909967171
1995	17.2605391115517
1996	15.7672939365417
1997	16.015130807865
1998	16.7011082856411
1999	15.2580757461935
2000	13.5909480276924
2001	13.2070435298578
2002	12.0551611624532
2003	13.4694247561217
2004	14.4825005007376
2005	16.6190180757235
2006	17.5404247180092
2007	17.8640856862195
2008	16.5098337370558
2009	15.6600552489802
2010	16.0437444354595
2011	17.316962856526
2012	15.732973360913
2013	17.3493138262499
2014	16.2538398153488
2015	15.3430503454798