Estimating the bankroll's rate of return is difficult because of how many variables there are, but I'll give it a shot:
In 2021, bustabit saw 27,398,415 XDR in gross gaming revenue and the bankroll's current size is 39,339,068 XDR. Let's assume that the gross gaming revenue will be the same going forwards and let's also assume that the commission rate will stay the same at its current 80.9%. Further assuming there are no investments or divestments, that represents an estimated return of 5,233,097 XDR or 13.3% for bustabit's bankroll in 2022.
In reality, players won't win/lose exactly the same amount they did in the past, the commission rate will continue to change with the size of the bankroll and Bitcoin's price and investors will add to and remove from the bankroll. These things are difficult to model, though, and require more assumptions of their own.
For bustadice it's even more difficult because its revenue is less consistent and the bankroll is still recovering from a loss in early 2021. Using the same methodology as above I arrive at an estimated rate of return of only 0.3% per year. In reality, its average annual revenue is larger than it was in 2021 and the bankroll will probably decrease in size once it reaches its all-time high profit again and it starts paying the commission again.
another question - from the .csv data looks like sometimes commission it taken from negative profit days. is it a mistake?
The commission is taken in real time whenever the bankroll's profit reaches a new ATH, so that can happen when players lose enough to generate a commission for bustabit and then win it back on the same day.