In your dashboard you find 'Visitors statistics'. Here you can see how many people have visited your location that day and in how many groups these visitors came to your location. These numbers are taken by the amount of faces that are counted in your photos. When you upload multiple photo's of the same people in one set, the faces will be counted just once.
Statistics - Visitors
When you want to see an overview of how many people visited your location over a different period of time go to 'Statistics' - 'Visitors' in the sidebar.
Here you can change the date and get an overview over a different period of time. You can view these statistics daily, weekly, monthly or yearly.