QUOTE(gxseries @ Aug 24 2008, 05:26 PM)

The only reason why I hesitate to say 1966 was because the 50 cents design was around back then. A new design was prepared in 1969, which is the 12 sided coin and hence I mentioned 1969.

The young Queen design ended in 1984 and hence named it as 1969-1984.
Good logic. It is a nice medal, but it would have been easier for us if they had dated it!