How is it decided how many coins each mint will produce? Is it supply and demand from each of the Fed Reserve Banks nearest each mint or is it predetermined that Philly will make XX amount and Denver makes XX amount. This question is in regards to circ coins not coins that go into mint / proof sets. Then again how are those amounts determined?
How many circ coins will be struck is determined by the supply demands of the Federal Reserve system. There is a formula the Mint uses to determine what that demand will be for the year ahead. As for the Mint and Proof sets - the number of these struck is determined by the number of orders for them the Mint receives.