SFStatic said:
Even in the heyday of Top 40, very few played more than 4 new songs per hour, and either had a Top 40, or Top 30, or Top 20, plus a few "adds. It's more than now, but even then, if you figure 16 songs per hour, it was only about 25% new music...and no one ever played the real up and comers in the mornings, so less then.
My memory is quite different. To me, the "heydey" of Top 40 was the mid and late 60s in LA. During drive time hours on KHJ, KRLA and KFWB, the ratio was generally 3 hits from the current play list (Boss 30/TuneDex/Fabulous 40) to one "golden" (oldie). That would be
12 current hits per hour, if you're assuming a total of 16. Perhaps only 1 or 2 of those would be "Hitbounds." During mid-days and nights, the ratio was 1 "oldie" to one current hit; or about 8 current hits per hour.
So at most, these stations were 75% new music (drive times), and 50% new music during other day parts. Also, keep in mind that the "oldies" were generally from the previous 3 to 5 years - many of them were closer to recurrents than oldies. They had a very short list of 50s songs they would play - but even those were no more than a decade old, usually less.
I paid less attention to the ratio when I moved to the Bay Area in the 70s, but I think it was more or less the same.