March 1989 - May 1989
September 1989 - November 1989
November 1990 - February 1991
October 1991 - December 1991
January 1993 - April 1993
February 1994 - April 1994
January 1995 - March 1995
January 1996 - March 1996
January 1997 - March 1997
January 1998 - March 1998
January 1999 - March 1999
January 2000 - March 2000