Administrators have access to downloading a full export of team performance data. You can do this from the Organization Dashboard.
This export, a .xlsx (Excel) file, includes all historic reviews within the selected timeframe along with overall participation statistics. The details from each review are all shared - when the review was completed, who the reviewer was, the question and category used, the answer they provided, and any feedback comments they shared.
To export historic review data...
Click on Dashboard and then the Organization sub-tab