One thing I've noticed is how some suburban areas which only twenty years earlier had been boomtowns - lost population during the 70s. Perhaps a result of the children moving out? Here are some examples"
IL 6 - Berwyn Cicero Oak Park Park Ridge (lost 8% of population in 1970s)
IL 10 - Evanston, Winetka, Skokie, Wilmette (lost 6% of population in 70s)
NJ 7 - western Bergen county (lost 7% of population in 70s)
NY 4 - SE Nassau (lost 8% of population)
NY 5 - SW Nassau (lost 7% of population)
NY 24 - Scarsdale, White Plains (lost 6% of population)
PA 7 - Delaware County (lost 10% of population)
Almost certainly that's the case. In my suburb there was one big build up from 1955 to 1975 and a second one that began in 1988 through 2007. That gap from 1975 to 1988 made the demographic bubbles much easier to see. School population topped out first in the late 70's early 80's as no new kids were moving in to the suburban tract housing of the 60's. By the early 90's the shrinking neighborhoods suddenly grew as retired empty-nesters left and new young families moved in. At the same time the new housing growth accelerated the need for new classrooms and significant school construction was completed in the mid 90's. The 60's-era neighborhoods are now going through a second generational transition, but it isn't as pronounced as the first one since the family ages are more spread out. A population decline in the newer subdivisions should begin to form later this decade as the children move out before the next generation moves in. After a couple of generations it approaches a steady population as the town sees in its century old neighborhood.
