1966 to 1966? 1967? 1968?
From 1966? 1967? 1968? to 1968/69
Sometime during 1982
From 1968/69 to June 1970
June 1970 to December 1971
May 1972 to June 1973
June 1973 to May 1975
Sometime during 1983
June to December 1974
June 1974
Early 1975 to June 1975
June 1975 to March 1976
October 1975
Sometime during 1984
Sometime during 1985
Early 1985 to June 1985
July 1985 to sometime during 1986
Sometime during 1987
Sometime during 1978?
April 1989
Sometime during 1989
Early/mid 1976
Sometime during 1989/90
Sometime during 1990
Sometime during 1991
Sometime during 1992
Sometime during 1981
October 1992
Sometime during 1992 or 1993
Sometime during 1993?
Sometime during 1993
1993 to February 1994
February 1994 onwards
March 1994 till later the same year
Sometime during 1994
April 1994
The summer of 1976
Sometime during late 1994
During 1995
July 1995
Sometime during 1995
Mid/late 1995
Sometime during 1996
Sometime during ?
August 1997
During 1998
Sometime during 1998/1999
During 1998/1999
Sometime during 1977
During 1999
During 1999/2000
During 2000
During 2001
March to April 1976
During 2002
During 2002/2003
During 2003