Using WietseWind's https://ledger.exposed/rich-stats, I prepared a table which shows movements in the (1) total number of accounts falling into each bracket of XRP accounts and (2) total number of XRP owned by each bracket. The account brackets are split based on the balance of XRP following the logic from Wietse's site linked above which I assume most of you are familiar with. I also added two tables showing the same information, but for merged brackets.
I prepared this only for my own use and did not intend to share it anywhere, but I thought that if there is at least one person who finds this useful, it may be worth sharing. I did not do any fine-tuning and just shared it in the simple format that I use, so for most people, it is probably too ugly to work with :).
I will not bother you with my own subjective interpretation of the data.
The first two time periods (*H2/2018 and *Q1/2019) have odd opening / closing dates as they are simply based on the dates when I had originally captured the data. For me, the aim of this table is just to get a high level view as to how the XRP balances and numbers of accounts develop in each time period, so it does not represent a big issue. I intend to keep updating this table each quarter using the right opening / closing dates as the parts of the table which are not yet filled in indicate. At the end of the year, I will probably also make one showing the trend for the whole 2019.
Bear in mind that the first period is of a different length, so that it is not comparable with the others without some extrapolation of the data.
The data on Wietse's site update frequently, so that it is probable that when you check the site, there will already be slightly different figures.