Year	% of total electricity output
1990	90.9291303868621
1991	93.2719103679691
1992	94.6855308524551
1993	96.488360295361
1994	98.2864209162643
1995	98.4553119730185
1996	98.426503784358
1997	97.9150303463049
1998	98.10705866038
1999	97.6577831233779
2000	98.4417772162561
2001	98.7762480878876
2002	99.0981571036466
2003	98.9520867405657
2004	99.0782851252198
2005	99.2802808660035
2006	98.6182462356067
2007	97.8278266834343
2008	97.8509939926921
2009	98.6535955823044
2010	99.7870398539702
2011	99.7659810321468
2012	99.5640391186521
2013	99.7429155711364
2014	99.0286546867411
2015	98.4733714019345