There's this page: https://bitcointalk.org/index.php?action=stats

I have no idea how accurate some of the data is there, and haven't checked it in a while. Seems like 7994.49 is the average posts per day, however that seems hard to believe, and I would say its much more than that. Also, it seems like it only tracked up to December 2017.

The top posters, and some other data seems to be up to date though.