Seriously, most decades style does not develop immediately at the turn of the decade. It's usually something like 3, or even five years in, before you really see the styles, trends and fashions that everyone comes to associate with that decade.
So the 60's ran a bit over in the 70's, probably till about '72-73. The 70's held on pretty strongly through the early 80's. I found my old college yearbooks online, and was looking through the senior portraits and such for old friends of mine and stuff. Now I graduated in 1983, but you really didn't see the typical '80's haircuts and clothes on people until about 1985 or even '86. And even then, mostly the girls and not the guys. Now granted, this was the backwoods of Maine, but there were enough kids there from the civilized states like Mass and NY.
But the kids from 1980-1983 looked just like the kids in my high school yearbooks from the late '70's.
