What is the total supply of mantle?

Could you please elaborate on the matter of "What is the total supply of mantle?" I'm interested in understanding the exact quantity of mantle that exists or will be available in the future. Is the supply finite or infinite? If it's finite, what's the specific number? Also, is there any mechanism or plan in place to adjust the supply in the future? I'm particularly interested in how this supply might affect the market value and scarcity of mantle. Could you provide some insights into these points? Thank you for your time and expertise in this matter.