In the audit trail tab of a document or folder, there are only recent entries when there is more data in the audit trail table that has not been truncated
1. On the Audit trail tab, note the date filter at the top of the screen, it was only showing "Records from the last 30 days"
2. Hit the Customize... button
3. Select the Date tab
4. Change the drop down to the time frame you would like to see