Sean O'brien has seen concerts during 15 years.

Year   Concerts Seen  
2019 1 concert
2017 2 concerts
2016 3 concerts
2015 2 concerts
2014 1 concert
2013 1 concert
2012 4 concerts
2011 4 concerts
2010 6 concerts
2008 1 concert
2005 1 concert
2000 1 concert
1999 1 concert
1998 5 concerts
1997 2 concerts