Since a new account must be funded from an existing account, I’ve modeled the existing accounts in terms of parents and children. Since accounts can be merged, a single account could actually have more than one parent at different times. This is uncommon, but has happened in the existing blockchain. The directed graph below shows accounts as nodes and the parent-child relationship as edges. The node size is relative to the number of children. The nodes with no children have been removed from the graph since there are so many of the childless nodes that it obscures the other data.
In general, there are a few large parents and lots of small parents. The large parents tend to be related to Stellar.org or an exchange that trades Lumens.
Let me know in the comments how else you would like to see the data represented.