I happened to stumble upon a bunch of blogs about thrift store findings. Probably a semi-conscious stumble as this, to some degree, is a hobby of my own. The blog called The Art of Finding made by "an artist and a mother and a professional level thrift shopper" was one of the better. For instance, in one post she writes about finding a bunch of binders - one for each year, 1961 and throughout the eighties - and how you can see the design change with time.
The photo is from one of the binders. What year? Around 1970 I guess.