May 2001
4.50
September 2001
3.75
November 2001
3.25
December 2002
2.75
March 2003
2.50
June 2003
2.00
December 2005
2.25
March 2006
June 2006
August 2006
3.00
October 2006
December 2006
3.50
March 2007
June 2007
4.00
July 2008
4.25
October 2008
November 2008
December 2008
January 2009
March 2009
1.50
April 2009
1.25
May 2009
1.00