Year	% of total electricity output
1990	19.362039050118085
1991	19.233567773909318
1992	19.158396961620987
1993	19.787949969372956
1994	19.538118578507383
1995	19.835356089612507
1996	19.50510302097833
1997	19.38296656718015
1998	19.036184125767154
1999	18.66458400136925
2000	18.333154872472388
2001	17.869591131094936
2002	17.78865440861129
2003	17.378554167553485
2004	17.809716279328775
2005	17.97509024185524
2006	18.11623198734796
2007	17.881396718673965
2008	18.554747585868753
2009	19.33418182184826
2010	19.56099754508148
2011	19.932825015208422
2012	20.901536405427123
2013	21.710345844235587
2014	22.40725845260128
2015	22.85445608159794