As a matter of curiosity, is the proportion of question with at least a top-level tag the same in the last few years (2017–)? I'd guess that there was more retagging in the last few years, but I'm not sure.
1. We can easily modify those search queries to restrict to questions created in specific date range or see results for each months, etc.
2. It is quite easy to decide whether or not to include deleted questions or not.
However, in this way we see the tags which the question has now. So even if a top-level tag was added to some question from 2017 only recently, it will still count.
If we wanted to get state of tags at some point in the past, we would have to look through the PostHistory table. I think this would be rather complicated (beyond my knowledge of SQL). And even if this is doable, the query will probably be complex enough to run very slowly.
It would be also possible to download SQL dump of MO - they are saved quarterly IIRC. But I do not really know how to work with them. (I think they are in xml.)
Just to clarify, this shows percentage of questions which were created in the given month.
I am not sure how whether this can be modified easily to get the questions created until the given month.
I might ask around how to do this - but at the moment I will probably be busy with other things. (So if somebody with good SQL knowledge is around, maybe you could help.)
You can see lower numbers in the second half of 2013 - my guess is that the users who were active in retagging were more active at the time. For example, this room was created in August 2013.
Do you think that lower percentage at the time is simply because you and Ricardo Andrade were more active during this period? (The first months after the MO editor's lounge was created.)
@MartinSleziak it's plausible. Ricardo certainly edited a lot during a certain period of time. And a ten percent difference is just about five questions per day. That's plausible. There were times when I quite systematically paid attention to this. I don't know when exactly though but yes seems likely. There was a good dynamic during some time.
