Year	% of total electricity output
1990	22.507118945107372
1991	20.538154687412852
1992	19.52967184984092
1993	19.50767772999554
1994	19.40981118462361
1995	20.223535255564784
1996	18.601263446650226
1997	17.75972526038333
1998	18.342323507145082
1999	17.665269205664075
2000	17.739269913977108
2001	19.55724099174872
2002	18.11278124610194
2003	15.793253267543616
2004	16.591398946505475
2005	16.398298511567603
2006	15.994648348746903
2007	15.660088046066305
2008	17.893870039059806
2009	17.960607001609873
2010	18.417155866128766
2011	17.052452387989526
2012	19.97457274449165
2013	20.263184225065846
2014	22.309298169636175
2015	23.39468534968163