Jogging...
The zinc-wafer copper-clad penny came about in the early eighties as a fix for the cost problem. Here's a decent Wiki article about the one cent coin.
Been meaning to figure out how much it costs to produce our other coins given the current metals bull market. Just about every metal is seeing record prices. Coin specs can be found on this page from the US Treasury. Even the Nickel is mostly copper.
I do love those old coins. Oldest I ever found in change was a 1919 penny. You can still buy a bag of pre-1964 90% silver coins from a coin dealer - price based on their silver content, not their face value.