This will be the closest for you to determine:
https://bitinfocharts.com/top-100-richest-bitcoin-addresses.html
The number is between 1 and the Number of Addresses holding coins. Several addresses can be owned by one user so its practically impossible to determine how much a given person actually owns. Unless you know all their addresses.
What this table shows is how poorly distributed bitcoin still is. To be expected given the Pareto principle.
1. it is super Pareto- 93% coins in 2.3% accounts. Realistically, it isprobably even less- 0.5-1% since people might use multiple accounts.
2. Excesses over Pareto (80/20) will smooth out over time, I believe.