So is this list of distribution only based on the addresses? Or is it based on another method? I could not find it.

I would suggest two tendencies:
1. Addresses with large sums are likely to be cold storages of exchanges or storage services like blockchain.info
-> Per address there are many individual holders.
2. Individuals with largs amounts tend to have differend addresses.

Just one example:
Let's assume I have 8 coins and split them up on 4 different addresses. Then I bought for my family (4 individuals) 0.5btc each and to make it easier for them I add all of them to one address.
address1 2
address2 2
address3 2
address4 2
address5 2
-> On the blockchain this would appear as a perfect distribution.

Another example:
990 individuals store their 1 coin on blockchain.info and one person has 10 coins, and stores them in one address.
address1 990
address2 10
-> On the blockchain this would appear as vastly unequal, but in reality it is.



This leads to the conclusion that the wealth distribution ist not really easy.