Are there any published stats about voting in HN? Like daily/monthly number of upvotes/downvotes, etc.

I think you might be able to get at some of that through one of the HN APIs, but it would be aggregate in the sense that you would get the total score of a story, not the votes that comprise it.

- https://github.com/HackerNews/API

- https://hn.algolia.com/api