William Gannon has seen concerts during 24 years.

Year   Concerts Seen  
2023 1 concert
2018 1 concert
2014 1 concert
2010 1 concert
2009 1 concert
2008 2 concerts
2007 2 concerts
2006 1 concert
2005 11 concerts
2004 4 concerts
2003 6 concerts
2002 6 concerts
2001 13 concerts
2000 15 concerts
1999 11 concerts
1998 1 concert
1997 2 concerts
1996 3 concerts
1995 18 concerts
1994 6 concerts
1993 5 concerts
1991 1 concert
1989 1 concert
1987 2 concerts