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Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 8:16 pm
by Nystagmus
Hi, I'm a long time lurker but I've been sorting copper since about 2006. On my Christmas break I stayed with my parents in Southern California. My dad knows about my sorting and offered to let me sort some old change he's "socked away" since the early 80's. He has a basket that he throws change into and when it gets full he empties it into an old sock. We sorted through dozens of socks and it was possible to tell when it was stored away by the newest dates of coins in each batch.
I know lots of posters on this site give exact numbers, but because of the time involved in sorting I can only give you estimates from the hand sorting. For each sock I made zinc and copper stacks which were about equal in height. This made it fairly easy to make percentage estimates. Here's what we found:
Copper percentages by year. The newest sock was put away in 1997 and the oldest was 1984:
1997: 35-40%
1992: 40-45%
1987: 45-55%
1984: 75-85%
Most of the socks had the newest coins from one of these 4 dates which is why I didn't include other dates. I seems that zinc production "significantly" altered copper percentages before sorting became popular. I've picked up boxes in the area in 2010 and only found about 18% which leads me to believe more in the theory that copper percentages are decreasing due to the introduction of new zinc rather than any effect of sorters (unless you live in an area where major sorting is going on).
Re: Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 8:51 pm
by TXBullion
Vert cool especially since there really is no way to get any "old" data like this even if it is rough
Re: Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 9:12 pm
by 68Camaro
Interesting and rare data, and I'm sure relevant and useful in some way. But I'm not sure I can draw broad conclusions from it.
Average annual production in each decade
1920s: 166 million
1930s: 220 million
1940s: 1.1 billion
1950s: 1.1 billion
1960s: 3.3 billion
1970s: 8.1 billion
1980s: 12.3 billion
1990s: 11.4 billion
Zinc penny production from 1983 thru 1999 was north of 195 billion. There were more zinc pennys coined during those 17 years than all copper pennys in prior history put together back to the start of penny production in the mid-19th century. If every penny every made had never left circulation the zincs would have *still* diluted the percentage down below 50% by the end of the 90s.
By the end of 1984, the 2+ years of zinc penny production amounted to about 30 billion. If 30 billion is 20% of the penny population (per your stats), that suggests that the coppers in circulation were 120 billion, and would indicate that 2/3 of the copper pennys ever produced were still circulating. I really don't believe that, but let's stick with that for now. If they were still circulating in 1984, I would expect most of them would still be circulating 3 years later, so after another 3 years, another 30 billion new zinc pennys, and (if we assume few losses) the total circulating number would have grown from 150 billion to 180 billion, and the 120 billion copper pennys should amount to 67% of the population now. But your data shows the percentage had declined to 50%, which would suggest that a whole lot of copper pennys got pulled from circulation; if the percentage was 50% then the number of coppers match the 60 billion zincs, and therefore the coppers declined from 120 billion to 60 billion. That says half the coppers in 1984 disappeared by 1987. I'm not sure I believe that. So something is amiss here. I suspect that some of these numbers, while interesting, and real for your dad, for whatever reason must not be a good "sample" for the larger population.
Re: Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 9:54 pm
by 999Ni
That data sure does "stink"!
Sorry just had to say it.
Um interesting data for sure. Of course new zinc production will lessen cu% when there is a finite amount of cu left. However, although not the main cause of the cu% decrease, i still do think sorter have made the cu% lessen at maybe a slightly faster rate. But there are other factors to consider as well, like destroyed coins, or people turning change into the bank, which affects the % and there's no way to really account for that, so......
Re: Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 11:41 pm
by HoardCopperByTheTon
Great first post Nystagmus! Welcome to the forum.
The other factors to consider when estimating the dilution caused by the introduction of new zinc cents are the lag time from the time of minting until they actually appear in circulation.. and the ecomomic vibrancy of an area, which can seriously affect the introduction of new coins, and therefor the dilution of the copper percentages of that area. We still see significant regional differences today because of this.
Re: Historical averages in the zinc era
Posted:
Fri Jan 07, 2011 11:45 pm
by HoardCopperByTheTon
I agree that the introduction of new zincolns has a much more deleterious effect on the copper percentage than the efforts of a few sorters. I live in an area of what might be considered serious sorting. As a matter of fact I am getting together with a couple of other local sorters at a local coin club that both members of the multiple ton club.
Re: Historical averages in the zinc era
Posted:
Sat Jan 08, 2011 1:20 am
by Nystagmus
Thanks for the comments. Regional differences can be huge. I have family in Montana and routinely load up on CWR boxes when I visit. I picked up 8 boxes during Thanksgiving which had the following yield:
Box 1
934 copper 37.36% 6 wheat 45 S mint
Box 2
871 copper 34.84% 7 wheat 24 S mint
Box 3
533 copper 21.32% 3 wheat 19 S mint
Box4
529 copper 21.16% 7 wheat 19 S mint
Box 5
876 copper 35.04% 6 wheat 27 S mint
Box 6
794 copper 31.76% 8 wheat 41 S mint
Box 7
736 copper 29.44% 3 wheat/1steel 18 S mint
Box 8
997 copper 39.88% 7 wheat 35 S mint
Total average 31.35%
I would have had to sort twice as many boxes in CA for the same amount of copper!
Re: Historical averages in the zinc era
Posted:
Sat Jan 08, 2011 11:52 am
by HoardCopperByTheTon
Nystagmus wrote:I would have had to sort twice as many boxes in CA for the same amount of copper!
That's why we sort more in CA. "If your percentages are low.. just sort more!"
Re: Historical averages in the zinc era
Posted:
Sat Jan 08, 2011 12:50 pm
by slickeast
Zincs have a shorter life than copper. Look in your zinc rejects. You will find zincs that are pitted and chewed up from who knows what. How many zincs are lost every year do to the elements is unknown.
Like HCBTT says, just sort more.
Re: Historical averages in the zinc era
Posted:
Sat Jan 08, 2011 7:23 pm
by Nystagmus
In some of the older socks there were zincs which had decomposed just enough that they would stick to the bottom of the sock. The only way to get them was to actually rip them from the fabric. Also, a lot of the early 80's zincs looked like they were delaminating.
Re: Historical averages in the zinc era
Posted:
Sun Jan 09, 2011 10:35 am
by misteroman
What made you guys decide to open them up now? Was the time just right?
Re: Historical averages in the zinc era
Posted:
Sun Jan 09, 2011 10:38 am
by HoardCopperByTheTon
It's the economy. People are going in their sock drawers and cashing in all that change they had socked away. This is why many of us are finding silver and better copper percentages in our sorts.
Re: Historical averages in the zinc era
Posted:
Sun Jan 09, 2011 6:11 pm
by Nystagmus
I had 100$ face which I was able to get delivered from Montana. After going through all of it my dad was interested in how much copper might be in the socks. Plus there wasn't much to do with all the rain storms going on at the time. It actually took about 3 days to go through all the socks..filled a 2 gallon bucket about 80% full of copper. My dad's been into coins since he was a kid so there were few wheats and only 3 silver(which he was surprised I found). There were also some foreign coins from Mexico, Uruguay, Germany, France, Canada (3 pre-1980 nickels), some middle east country, and a few other I can't remember off hand.