There are some statistics on Worldbuilding.SE on Area51. Some other sites have a community wiki topic where the statistics are recorded every week or every other week. Do we want to make something like this?
The statistics for the first few days are misleading, so starting this before day 7 doesn't seem to be a good idea, but at least we have time to discuss it how to do it (if we want to).
For full disclosure: I can't volunteer to become WB.SE's record keeper if the community wants to establish this function.