Fuel to the fire......
Using iluc’s mintage numbers posted above, along with other references to narrow down just Lincoln cents
http://www.coin-collecting-guide-for-beginners.com/lincoln-penny.html,
and with these four exceptions:
•1943 mintage not included in totals
•1982 mintage divided in half between copper and zinc
•2011 mintage not included in totals
•Totals do not account for attrition removal
One could conclude:
Total copper wheat cent mintage 24.724 billion
Total copper memorial cent mintage 149.787 billion
Total copper cent mintage (24.724 + 149.787) = 177.511 billion
Total zinc memorial cent mintage 275.480 billion
All total cent mintage (177.511 + 275.480) = 452.991 billion
So using those numbers the % of copper in circulation would equal total copper / total mintage or (177.511 / 452.991) = 39.19%
*My average copper percentage per bag equals 31.51% after 278 bags sorted, so:
31.51% of 452.991 billion equals 142.737 billion, therefore (177.511 – 142.737) = 34.774 billion copper cents removed, or -19.59%, if my personal copper average is the norm.
But using a range of 20% to 30% instead of an absolute 31.51% would conclude:
30% of 452.991 billion equals 135.897 billion, therefore (177.511 - 135.897) = 41.614 billion copper cents removed, or -23.44%
20% of 452.991 equal 90.598 billion, therefore (177.511 – 90.598) = 86.913 billion copper cents removed, or -48.96%
Looking at the 50 year chart for copper, one could argue that true hoarding probably took hold with the spike in copper above $4000 per metric ton…approx. 2006 to present…so the last 5 years would be considered true hoarding…..of course a disclaimer could be inserted here.

Thus 30% remaining copper in circulation required removal of 41.614 billion coins. Dividing that by 5 years results in 8.323 billion copper coins removed per year, which would produce an estimate of (135.897 / 8.323) = 16.33 years to remove the remaining copper from circulation….
At 20% remaining copper in circulation a removal of 86.913 billion coins was required.
Dividing that by 5 years results in 17.282 billion copper coins removed per year, which would produce an estimate of (90.598 / 17.282) = 5.24 years to remove the remaining copper from circulation……
Of course these are only fantasy calculations due to data assumptions on my part, but a close examination of the copper percentage change over time would reveal a close approximation of when copper cents will be extinct…..
hags