So there is a way to approximate. Assume for a given denomination of say $5 notes.
Total denomination liability = 200 M notes (example.. didn't check table)
*minus*
Total printed in most current series (all variations in the year of record YOR)
= the total notes of all older YOR's.
A start, assuming total denomination liability float by replacing worn notes from current YOR.
Now if you estiamte an increasing note withdrawl rate on each year of record (1972, 1954, 1937, 1935) you can approximate how many would be left. I'm sure this forum could crowd-source the right factors. Or inferrred from market values.
Not exact but would give you a "rarity factor".. "patent pending" ;-)
My assumption is few 1954's are being turned in and no one is turning in 1937 and older on purpose... like a $500 above - my word! I can't believe it wasn't harvested somewhere before the furnace! like maybe it's in BOC museum vault and therefore not deemed in public circulation (one would hope so, unless you've got one).
I can't help but believe this is unoriginal thinking and that someone has plugged the math into a spreadsheet at some point. I know a rocket scientist and a brain surgeon and I'm not a smart as either of them
Here's hoping!