Wiktionary
midseventies
n. 1 The middle years of the 1970s. 2 The middle years between 70 and 80 years old.
Usage examples of "midseventies".
It was a style and a look that had faded away in the midseventies, but if you were the King of Adventure, I guess you could dress any way you wanted.
A short, stringy man with a shaven head and an enormous walrus moustache, Rummel was in his midseventies and looked more like a Sherlock Holmes villain than the owner of six huge auto salvage yards.