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11:32 AM
At the moment there are 843 questions with deprecated tags.
There were 906 questions with deprecated tags a year ago. So the count decreased by 63 questions in one year.
There were 1000 such questions in August 2017, 900 such questions in June 2018.
You can also compare this with numbers from May 1, March 3, November 27, August 25.
with 307 questions, 173 if we omit the most frequent algebra-related top-level tags and 95 questions with no top-level tags.
with 377 questions, 227 if we omit frequent geometry-related top-level tags and 130 with no top-level tags at all.
contains 160 questions, 76 if we omit co.combinatorics, 38 with no top-level tag at all.
Also deprecating of (convexity) was discussed on meta.
The are 165 questions where was removed, 739 questions where was removed 81 questions where was removed.
You can find queries returning those posts here: chat.stackexchange.com/transcript/message/49179918#49179918 You can even check which users have edited them away: chat.stackexchange.com/transcript/10243/2019/4/28
As I have mentioned before, it would be not difficult to prevent deprecated tags at least from being added to new questions: The existing deprecated tags should be blacklisted and Blacklisting (deprecated) tag while they still exist.
There are 103129 questions on the site, 80412 questions with a top-level tag, 85379 questions if we also count (linear-algebra), (graph-theory) and (set-theory).
22.028% of questions without top-level tags, 17.211% of questions if we take the less strict interpretation.
Here are the links used to find the posts with top-level tags: chat.stackexchange.com/transcript/10243/2018/10/27
 

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