January 2002 - December 2002
April 2001 - December 2001
November 1998 - March 2001
January 1998 - November 1998
July 1997 - January 1998
July 1995 - June 1997
July 1993 - June 1995
July 1989 - June 1993
January 1988 - June 1989
January 1986 - December 1987