If we group the decades in history from mid-decade to mid decade, we would have a different conception from the 60's, 70's, 80's, etc. groupings.
I used to see them that way. Like the early 70's were still alot like the late 60's. (In music, the pre-disco era) The late 70's and early 80's were also similar (the disco era, until complete digitization in the mid-80's killed it off), as the late 80's and early 90's. (total digitization until the "retro" kick took over). Now, it seems the late 90's to the present are very similar. Perhaps I'm just not noticing things as I used to. Electronics and computer technology is one thing that has really continued to change in leaps since the late 90's.
I will give my usual caveat to population and stats on the subject. How can you break down E/I, S/N, T/F when you have multiple variables to consider? For example if you say there are x amount introverts, you have to specify which introverted function being referred to. Is Ni, Si, Ti, or Fi? The same goes for extraverted functions and then the S/N and T/F have two variables to choose from. Until there is a study done using cogntive functions, any population reference is skewed when using dichotomies.
Besides Jung does not refer to any rare type except that anyone claiming to use 100% of a certain function is rare. For that reason I continue to say there are on average 6.25% across the board with many not actually showing a type as Myers-Briggs alludes to in her book, but are products of the environment and expectations, ie ESJs are the typical western culture type.