the old WABC Suveys(which I collected and still have) were as exciting as watching paint dry;
a new record getting added was a major event, the same hits week after week, for what seemed like all eternity(but we listened cos it was WABC!!!, home of the hits!),with some recurrents, or 'new gold' as it was called at the time;
now this was early to mid 70s we're talking here, all helen reddy and charlie rich, michael jackson and donny osmond, until the early disco records(barry white,rock your baby, rockin chair, rock the boat, etc)started to pick up the tempo a bit;
songs stayed in the top 10/14 for at least two,sometimes close to three months from first appearance to final exit; some records stayed in the #1 spot for 4, 5 or 6 weeks alone, and then would begin a slow descent;
I'll dig them out during the week and post some examples