Generation X starts with those of us born in 194-1965. Being somebody born in 1965, I've been well aware of this generational cut off line.
The concept of "generations" is always a rather nebulous concept, but people do try to tie it to real demographics. 1964-1965 is important in that those years were a nadir in births in the United States, following on the heels of a petering out Baby Boom.
Those of us born during this two year period saw some real demographic changes growing up. Our classes in school were much smaller than the older classes. In my particular elementary, our class was so small that for several years, we were split up and placed in classrooms of the next older and younger grade.
I'm pretty sure that other people in my age bracket can confirm that schools had been used to dealing with much larger class sizes and as our age group when through schools, they had to start dealing with a much smaller population of students.
For me, this continued through my first years of employment. I worked for five summers at a theme park when I was in high school and college. The wages were pretty low (thanks Lamar Hunt!), in part because the theme park had been flooded with young workers during it's first decade of existence. When my age group started working there, the company started having problems finding workers. They had to start jacking up wages, starting out in food service (fast food chains were paying much better during those years).
I don't have much data to support this hunch, but I suspect that the problems I've had finding employment over the course of my adult life is due in small part to demographics. The level of jobs that I've been trying to get are glutted with Baby Boomers who have parked their asses, especially in the library profession where job turnover is much lower than other professional industries.
Somebody who I consider to be the "oldest Generation Xer" is flying to KC to visit me tomorrow. She was born in August 1964, which is what I consider to be the start of Generation X.
Why?
Because my friend is an Assassination Baby. She was conceived on the night after JFK was assassinated in November 1963 and was born 9 months later in August 1964. If Generation X is a bunch of cynical, alienated, work-hating people, then it's logical that our oldest members were spawned in the wake of the JFK assassination and the turn of the 1960s towards something more turbulent.
Or we could blame it on the Beatles.
Chuck