Whats the total supply of zoi?
21 millions. It would be around 12 millions after the first 6 months.
This is not true, this coins source is based on XZC's source where a big error in the code allowed "hackers" to create an arbitrary number of coins for themselves using malicious zerospend transactions.
https://zcoin.io/zcoins-zerocoin-bug-explained-in-detail/You can't really tell how much coins where maliciously generated, until you do some investigations with the block explorer but probably a lot

I don't read code but the exploit has since been fixed on 28th March release right?
https://github.com/zoincoin/zoin/releasesAt time of bug, ZOIN was 'dead' with a CAP of a few thousand so it's less likely it was exploited than Zcoin & Zcoin now has a valuation of $15 million despite that.
Myself used Zoin to test the exploit actually because it wasn't fixed and if you check the block explorer, or rather the log files of the daemon you see lots of zero transactions (coinspends) before suddenly someone 'fixed' it by disabling the zeromints at all. The 'half dead' state was actually the best thing to happen for exploiters as you could test everything possible with very low difficulty and no one sniffing in the logs
Okay, crypto is a gamble and you should never invest what you can't afford to lose, I wish you all the best with this coin I just wanted to point out (again, if you check back my posts in this thread) that there is at least some caution needed when playing with this coin.
I will try to count how many coins were generated.