Year	% of total electricity output
1990	11.907665914241889
1991	12.587799127469056
1992	12.921670037545226
1993	13.440531594311022
1994	14.642590088649392
1995	13.578255639759615
1996	14.011742822415552
1997	13.528125154465902
1998	13.645960192743287
1999	13.617693226395014
2000	13.89748083994915
2001	14.901726073880482
2002	13.035701233345433
2003	13.573396356698948
2004	14.266751282917214
2005	13.51497940295268
2006	14.831376443540158
2007	15.82794367765625
2008	17.241221398098226
2009	19.37546125321472
2010	21.27674080858638
2011	21.505217589590334
2012	24.267015124107388
2013	27.84932330250131
2014	29.24295287369133
2015	28.71846879632899