mtalbot_ca wrote:Hi there,
I think you are close, but I remember looking at one of our fellow member's site (sorry I do not remember which one), and the attrition rate was 6% for normal years and 12% for key-dates.
Cheers,
Because I wasn't really satisfied with the numbers I got while not accounting for loss, I decided to see if I could include it fairly easily into the math.
I started with 10% across the board, but then saw this post and changed it to a universal 6% across the board. I did not vary based on key dates etc.
For those following the math, here is what I changed from my previous response:I eliminated Proofs and Matte Proofs from the equation. Most of these has mintages below 20,000. I also removed all of the individual Date/Mintmark combos with less than 100,000 minted total, for both ease of calculations and to make some of the figures not round down to "0". (I'd say since 11/50 years had mintages over 1 Billion, those are small potatoes). In statistics you are allowed to remove data if you don't want to use it and feel it's irrelevant (My math, My rules)
Using my discretion, I grouped everything by year (All 1909s, 1922's etc. I just combined all mint marks for a given year and that was the total minted). I modeled that this Theoretical 100,000 Wheatbacks was assembled in the year 1959, all at once. Using the 6% loss figure above, I accounted that for each year any given coin was in circulation, that loss took effect. For example, the 1958s were in circulation for 1 year, whereas the 1932 coins were circulating for 27 years.
For the equations, I took the 94% and multiplied it to the total mintage for that year, raised to a power of the years it was in circulation (1955*0.94*0.94*0.94*0.94) or (1955 total mintage*(0.94^4)) I did this for each Wheat year and got a total of 12,139,108,588 wheats theoretically still in circulation as of 1959. Even though this is an ideal case scenario, it should still be a little more accurate than the original numbers I posted above.
Here are the new Numbers split by "Decade"
- Wheat_Mintages_w_Loss.JPG (26.12 KiB) Viewed 1109 times
Shown above is that the ratio of 40s/50s is above 9 to 1 with the other years. This does make since though if you think about it for 2 reasons, the earlier ones were in circulation longer therefore you will have more "modern" wheats, and the other is the total mintages of the newer wheats compared to the earlier years. There were just plain more of th 40s/50s made, pretty simple. So IMHO those 2 factors are working directly against you and all of us, for having a good "solid mix" of wheats. That term may need some revisting as this math shows a 9+:1 ratio. I was not expecting that
This still doesn't factor in any remaining Indian heads or any different loss for '43 steels or VBDs, just starting from no pennies (Not true) and going from all 1909s in year one to some of each year, in year 50 (1959). Please point out any flaws in my logic
as I am no expert by far. There has to be someone else who can figure this out better than I and shed some light on the situation.