I wanted to add this label to the resource but I am unsure of the age, it comes across as 80s but may be earlier as I have read that monsoon clothing was originally produced in India from 1973.
It's a bit hard to see the shape of your dress in the photo. If you can get a better picture, maybe on a hanger, we might be able to help more. I suspect 80s though. I do remember that label, I think from the 80s.
Here's a better picture, I just noticed there is a very long size zip also, but am not sure if this is a later addition to save undoing the buttons
It looks very 80s to me, even the colours. I'm not really seeing 70s. You may be able to tell by examining the stitching if the zip is an addition, but I think it could be original to the dress.