The dress has a '70s look but the labels look more late '70s to early '80s.
A couple of questions: what is the collar like (big, small, pointed - it looks large and pointed but I can't be sure with the black) and there any other labels? Is it a self-covered belt.
I suspect it's mid '70s but the collar could change that.
It's a pity they didn't line the buttons up with the flower centres, that would have been a nice touch.