In the "Statistics" tab, you can see activity data per unit / department.
Click on the "Statistics" tab and select the desired contact, at the top left. Select "Activity per unit" in the drop-down menu named "Report type", at the top left. You should now get various data applicable to your device, including activity score, number of sessions, minutes, days and degree of satisfaction. Activity score is calculated by: Sessions * Days * Minutes
You can filter the results by time period by using the drop-down menu called "Period".