Year	% of total electricity output
1990	21.28478242698105
1991	19.391139996876486
1992	18.519446306580843
1993	18.635395175274468
1994	18.59605543940846
1995	19.462255433856253
1996	17.97215013734477
1997	17.253340835025476
1998	17.86290768402659
1999	17.21727208578508
2000	17.343717333925817
2001	19.199260549873422
2002	17.770305628376466
2003	15.433759713133304
2004	16.25854424234141
2005	16.083796340628446
2006	15.727053484594464
2007	15.400806885422018
2008	17.64779566410993
2009	17.75892834508355
2010	18.22308335555452
2011	16.868158626081577
2012	19.805665107301625
2013	20.099068840850244
2014	22.17043677019815
2015	23.293733031546317