Copper Penny Attrition

[schockergd]

I saw this in the nickel thread, stating that should the balloon go up and the mint end the nickel that there would be 'Only $34 per person to hoard".

Now I'm not going to get into that, however it did spark my interest - exactly how many pennies have been hoarded in the US for their copper value (only).

So what I did was this to come up with a solid answer :

The US mint has spent quite a bit of money on research on how long a coin lasts. They determined through many studies that every coin sees a 2.5% yearly attrition rate, meaning that 2.5% of any given coin is taken out of circulation a year. Now having said this , these studies were done AFTER 1964 which means that they were based either on nickels , zincs or copper with most of the research being done in the past 10 years.

Now , taking that information and building out a excel spreadsheet based on mintage numbers, we get the following : There were 158,150,469,073 copper cents minted from 1959 through 1982. Compare this to zinc production (1982-2010) which was 185,967,784,345.

Now , these number seem close , but once we figure in a yearly attrition rate (which *should* exclude hoarding, but does factor in collectors) we come up with 63,362,707,081 coppers and 185,967,784,340 zincs still in circulation today.

Now , this means that while copper sorting, you're seeing an average of 34.07% coppers per box............but you're not.....you're seeing 25% or less. So this means that right around 9% of all copper pennies have been hoarded! Running the numbers again , it seems that pennies are really seeing about a 3.5% attrition rate, 1% over the norm, which I figure is from hoarders. This is interesting, as it also means that if we keep it up, we'll be seeing less than 5% coppers in circulation within 20 years or so, pending nothing changes and zincs still are being made and the mint doesn't intervene.

[Corsair]

Very interesting stuff, but I think your math gets a little fuzzy around the end. You subtracted 25% (reported average) from 34.07% (mathematical average) to get approximately 9%. That's, of course, correct, but when you state that "9% of all copper pennies have been hoarded," that's incorrect. 9% of all copper pennies that didn't disappear due to attrition have been hoarded. I believe you want to say that nine percent of 63 billion have been hoarded, not nine percent of 158 billion.

Still, that's some great math and great information. Thank you.

[Rodebaugh]

That's the contribution I am talking about. Nice work.

[HD-Daddy]

Yeah Impressive math! Somebody likes their Excel. I agree with Corsair though, Gotta count attrition in there.

[Oakair]

Although copper pennies have been subjected to attrition for longer periods than have zincs...(simply because they have been around longer), Zincs are more likely to fall victim to attrition due to their more fragile nature...

Cool post though, I hate math lol

[Morsecode]

Great post. I wonder though, does attrition mean the same thing to all coins?

Pennies disappear into cookie jars for years at a time, and re-enter the system, and then back to the jar again. Few people hoard longer. If this were not the case, wouldn't cents from 1971 already have completely disappeared (2.5% x 40 years)..?

I did spend too much time in the sun today so my ciphering could be off.

[Oakair]

Great post. I wonder though, does attrition mean the same thing to all coins?

Pennies disappear into cookie jars for years at a time, and re-enter the system, and then back to the jar again. Few people hoard longer. If this were not the case, wouldn't cents from 1971 already have completely disappeared (2.5% x 40 years)..?

I did spend too much time in the sun today so my ciphering could be off.

That would be assuming no new additions after (or before) 1971...

There is no guarantee which dates are lost to attrition, except my contention that zincs succumb faster than coppers

[68Camaro]

...
Now , taking that information and building out a excel spreadsheet based on mintage numbers, we get the following : There were 158,150,469,073 copper cents minted from 1959 through 1982. Compare this to zinc production (1982-2010) which was 185,967,784,345.

Now , these number seem close , but once we figure in a yearly attrition rate (which *should* exclude hoarding, but does factor in collectors) we come up with 63,362,707,081 coppers and 185,967,784,340 zincs still in circulation today.

Now , this means that while copper sorting, you're seeing an average of 34.07% coppers per box............but you're not.....you're seeing 25% or less. So this means that right around 9% of all copper pennies have been hoarded! Running the numbers again , it seems that pennies are really seeing about a 3.5% attrition rate, 1% over the norm, which I figure is from hoarders. This is interesting, as it also means that if we keep it up, we'll be seeing less than 5% coppers in circulation within 20 years or so, pending nothing changes and zincs still are being made and the mint doesn't intervene.

Not discounting the work at all, very good early post, but the same or similar work has been posted in the past. They are just admittedly hard to find with the format of the forum. What is good is that its an independent assessment that comes up with same end numbers.

But small math error. If you calculate 63M Cu and 186M Zn, then the percentage of Cu in those is 63/(63+186) = 25.3%, which is more or less what the accepted yield is. I'm actually seeing 18-19% here, and others are seeing even lower numbers (mostly in south) 13-15% while people more to the north seem to still see 25% up to 40%. So I'm not sure what to do with the balance of your predictions numbers as there isn't enough data. But with 63 billion as a source, all the RCers (and other non-RC penny forums put together) collectively probably haven't sucked away more than a couple billion of those, even counting the big dogs and the ebay sales. I think we might have seen maybe a 10% drop in the source, from 63 to say 57, which drops the yield only a couple of percent, and we don't have enough data to be sure of that small of a change.

[schockergd]

I'm a member of another coin forum, and one guy has roll-searched well over 250,000 nickels which is a VERY statistically relevant number. He has saved & documented all nickel finds prior to 1960, and interestingly enough his numbers show that what the mint publishes as estimated attrition rates are right - even going back to Pre-Buffalo V nickels (1913 and before).

As for my wording, yes it was wrong - 9% of the remaining coppers that haven't fallen to standard attrition have been hoarded. 158,150,469,073 were minted, 43,942,618,239 should still be in active circulation. From members on here, only about 37,956,112,578 are still in active circulation. In other words, 5,986,505,662 (Nearly 6 billion) have magically disappeared that should still be circulating around.

What's also interesting to note is that it seems that there have been more than a few large operations to try and petition the government to allow smelting of copper pennies. One such operation in my area (that can't smelt legally) tried to get a local congress-critter to pass a law to allow smelting under HR 5512. It never came up for a vote however I imagine they've got quite a pile of copper pennies as they expected to employ 30 people full time just to smelt pennies.

[68Camaro]

No time at moment to go back and review the calcs, but the 6B hoarded number just seems believeable (not that that is worth a hoot).

We all think the smelt ban, which was intended to be temporary, will be lifted within 1-3 years. It will happen either when they feel they have enough zincs to keep things going without complaint, or when they decide to phase out the cent altogether (or some combo of the two). Time to sort is now. As soon as the ban is lifted, the Cu cent will not last much more than another year in productive numbers, and diminishing returns will apply which will make it rapidly increasingly difficult to be worthwhile for most people to sort and hoard in numbers.

[beauanderos]

No time at moment to go back and review the calcs, but the 6B hoarded number just seems believeable (not that that is worth a hoot).

We all think the smelt ban, which was intended to be temporary, will be lifted within 1-3 years. It will happen either when they feel they have enough zincs to keep things going without complaint, or when they decide to phase out the cent altogether (or some combo of the two). Time to sort is now. As soon as the ban is lifted, the Cu cent will not last much more than another year in productive numbers, and diminishing returns will apply which will make it rapidly increasingly difficult to be worthwhile for most people to sort and hoard in numbers.

I get pickups now of mixed "dirty roll" 2011's... with maybe eight or ten darker cents contained. No way am I gonna take the time to crack open the roll and then run them thru, subjecting my machine to additional wear and tear... for, potentially, two or three lousy cents.

[schockergd]

All depends on where you're getting coins from beau , I'm still getting 10-15 per roll which to me justifies it.

[cesariojpn]

I get pickups now of mixed "dirty roll" 2011's... with maybe eight or ten darker cents contained. No way am I gonna take the time to crack open the roll and then run them thru, subjecting my machine to additional wear and tear... for, potentially, two or three lousy cents.

Cut open the rolls, thrown them onto a table, do a quick scan, pick out the goodies, sweep the rest into a waiting soda flat, re-roll/bag them later for return.

How easy is that?

[myfundsarelow]

if all of this infomation were applied to a math class you all would get A+ PEACE!!

[Sheikh_yer_Bu'Tay]

This is interesting, as it also means that if we keep it up, we'll be seeing less than 5% coppers in circulation within 20 years or so, pending nothing changes and zincs still are being made and the mint doesn't intervene.

Hey! This is good stuff! You put some time into this and I appreciate your sharing with us. My averages vary so wildly, I am not going to "argue the assumptions". Your point is a sound one none the less.

I would venture that the copper (brass) pennies will disappear from circulation long before 20 years from now. Their intrinsic value is far too great for them to last that long.

Also, the zincs wear-out much faster than the coppers do.

[TwoAndAHalfCents]

Look on the bright side, attrition will eventually make hand sorting easier. You only really need to check the date if there is a Lincoln Memorial on the reverse. So when the day arrives where we mostly see shields, it will be easier to do a first pass reverse check to eliminate most of the zincs. I'm currently seeing 10% for the newer reverse designs so it's not worth the trouble to sort by reverse yet. That will probably change in a few more years.

[schockergd]

20 years is my estimate pending no major economic collapse , so on and so forth.

I hand sort nickels and machine sort pennies and am seeing major attrition for pre-60s nickels. Hopefully I can get my machine sorting operation up soon, I'm trying to figure out how to get 4-6 machines all going at the same time and paying someone to watch em

Anyways, I think we're seeing the death of the 'copper penny' although so many are in circulation now. It didn't take more than 15 years to end the wheat penny and push it out of common circulation , so I think maybe 10-15 years after the shield is when we'll start to see some major attrition.

[Corsair]

20 years is my estimate pending no major economic collapse , so on and so forth.

I hand sort nickels and machine sort pennies and am seeing major attrition for pre-60s nickels. Hopefully I can get my machine sorting operation up soon, I'm trying to figure out how to get 4-6 machines all going at the same time and paying someone to watch em

Anyways, I think we're seeing the death of the 'copper penny' although so many are in circulation now. It didn't take more than 15 years to end the wheat penny and push it out of common circulation , so I think maybe 10-15 years after the shield is when we'll start to see some major attrition.

One thing that I've always questioned was, because of the change to the Shield penny, won't people soon start to think all Memorials will have value, like people did with the Wheats? So, before long, do you think some old grandma will hoard anything with a Memorial on the back, let alone if it's copper or zinc?