April 28, 2018 July 8, 2018 Annual Meeting September 8, 2018  
       
July 9, 2017 Annual Meeting September 9, 2017 December 9, 2017  
       
April 17, 2016 July 6, 2016 July 8, 2016 Annual Meeting October 8, 2016
December 3, 2016      
       
May 2, 2015 July 8, 2015 July 11, 2015 Annual Meeting November 21, 2015
       
May 5, 2014 July 9, 2014 July 12, 2014 Annual Meeting September 6, 2014
December 5, 2014      
       
April 27, 2013 July 11, 2013 July 13, 2013 Annual Meeting December 7, 2013
       
April 28, 2012 July 12, 2012

December 1, 2012

 
       
April 30, 2011 July 9, 2011 December 3, 2011  
       
May 2, 2010 July 8, 2010 September 11, 2010 December 5, 2010
       
April 26, 2008 September 20, 2008    
       
May 5, 2007 July 14, 2007 December 1, 2007  
       
June 18, 2006 July 10, 2006 December 2, 2006 December 19, 2006
       
January 11, 2005 April 23, 2005 July 10, 2005 September 10, 2005
December 3, 2005      
       
September 12, 2004 December 4, 2004