The full article of the monetary supply of ETC is here: https://etherplan.com/2020/02/25/the-... The "fifthening" in Ethereum Classic is analogous to the "haleving" in Bitcoin. But in Bitcoin it is a discount of block rewards or supply of 50% every 4 years. In ETC it is a discount of block rewards or supply of 20% every 2.39 years, or every 868 days. BTC cap is 21 million. ETC cap is 210 million. Easy!!