Year % of total electricity output 1990 86.4077669902913 1991 92.1424829753798 1992 95.0500883912787 1993 93.9076225559649 1994 95.686374016747 1995 93.9861390565616 1996 95.7204948177867 1997 96.1744452945677 1998 96.3202192209826 1999 97.3291582243507 2000 96.1490163248221 2001 95.3083109919571 2002 93.9539860888176 2003 97.8565705128205 2004 97.5026757046022 2005 98.713944515892 2006 98.3164373642288 2007 97.4825174825175 2008 100 2009 99.9807766243752 2010 99.9867864693446 2011 98.5922214268671 2012 100 2013 100 2014 100 2015 100