1975 - 1982
September 1981 - April 1988
September 1981 - April 1988
September 1981 - April 1988
May 1984 - May 1988
May 1984 - May 1988
May 1988 - November 1992
1988 - 1990
May 1988 - November 1992
August 1992 - August 1996
August 1996 - August 2002
November 1997 - August 2002
August 1996 - August 1998
August 1998 - August 2002