If you go to your site’s admin dashboard and click on the “Reports” link, you’ll be taken to a page that lists all the reports that are available on your site. There isn’t a report that returns unique contributors, but there are a few reports that could give you some useful data:
- User Visits (the number of unique user visits per day)
- New Contributors (the number of users who made their first post during the report period)
You could get the exact data you are looking for if your site had the Data Explorer plugin installed on it. For sites on our hosting, the Data Explorer plugin is available on Business and Enterprise plans.