This repo contains a whitepaper about the Anonymity Sets of Privacy coins, in particular of Zcash Protocol coins, where they are often called Shielded Pools.
This is a graph of the anonset size of HUSH v3 mainnet during it's first 567000 blocks.
This is a graph of the anonset size of HUSH v3 mainnet during it's first 579000 blocks.