What is the total supply of DCR?

Could you elaborate on the total supply of Decred, or DCR, for those who are less familiar with the cryptocurrency? I'm curious to understand the specifics of its issuance model and whether there's a fixed cap or if the supply can vary over time. Understanding the total supply is crucial for investors and enthusiasts alike, as it impacts the potential scarcity and value of the coin. Could you provide a concise yet comprehensive explanation of the DCR supply?