Year % of total electricity output 1990 47.06611669963415 1991 47.39296962411734 1992 47.02617509810404 1993 47.15616837147154 1994 47.903047260417786 1995 45.30871660866847 1996 44.625423039398605 1997 42.97567258552297 1998 42.54951109249915 1999 42.73685374008742 2000 41.57129836565316 2001 41.3123352704426 2002 41.08636106924941 2003 42.482149491544185 2004 41.47831366810242 2005 41.79870626058308 2006 41.15295242493865 2007 40.125448286467915 2008 40.70854204401698 2009 39.98387868696679 2010 41.480757845498545 2011 41.38077809846879 2012 42.08861512733817 2013 42.57328357095514 2014 42.829952514083644 2015 42.22422029784533