Year	% of total electricity output
1990	19.47787955958183
1991	21.01329402113692
1992	20.02438267488969
1993	19.06310063690258
1994	18.502240535108484
1995	18.649589781980765
1996	18.049408544309475
1997	17.818495835534076
1998	18.87967876054065
1999	19.88270255170107
2000	20.597209186739438
2001	21.945705070931073
2002	22.01033807281442
2003	20.63263657177242
2004	20.905092512878433
2005	21.30802632927806
2006	21.571189973636322
2007	20.65004441519405
2008	21.447711081027155
2009	22.69095818931705
2010	23.732982018380444
2011	23.803551837578077
2012	24.091231695530492
2013	24.764098554546127
2014	26.58124078141291
2015	26.61663702378324