Is it possible that typically between 20% and 30% of questions on Mathematics end up deleted, or did I mess up something in that query: data.stackexchange.com/math/revision/1065654/1317136/…

Although it's quite possible that roomba is responsible of quite a large chunk of deleted questions.

@Martin query seems correct.

Thanks for having a look!

I did not really expect the deleted percentage to be so high.

and then you have nice roomba peaks for the 9 day, 30 day and 365 roomba.

It might be helpful for analysis of deletion if you could know the reason a post got deleted (owner, votes, mod vote, roomba) but that data is not in SEDE