Visualise addresses added (or changes added) in a given interval

Every now and then the local community gets together and edits for an evening. Last evening we had the goal of adding 1000 new addresses to our city.

Now, I know the hourly interval when the meeting took place, I know the bounding box where the edits took place - how can I easily count the number of addresses added?

If this is too narrow, how can I easily count the number of edits made during the meeting?