I've looked at the figures on Tarvin population in the recent articleby Ted Lush and they are interesting.
The one figure that stands out is the 5-15 year age range in 1981. Most of the others change in a more gradual way but the change of that figure from 1981 to 1991 is particularly drastic in falling from 629 to 358.
I think the drop was so large because of the demographic at the time when there were lots of young families from all over the country that were transient. Heath Drive school was full and they had to build Meadow Close for the infants. ICI and Shell had lots of people who moved from place to place every 3 years or so. Only the "locals" had grandparents in the area. All that meant that people had to build their own community and mutual support mechanisms. Paying for baby-sitting was unheard of. There was the tiddly wink group, the curtain ring group and others, based on one per hour before midnight and two after. It was a way of keeping track of who'd done what and every so often there would be a meeting to balance things up. One year there were 32 teams in the village quiz because there were so many organisations, some with more than one team.
Over the years people have put down roots and some of the young people have returned so that the generational profile has changed.
(Ed. I think I still have some unused curtain rings in the desk drawer!)