All dates of all User login (not just last date logged in)

We are working to track user engagement with Process Manager and it would be useful to see all the dates that a User has logged in, not just the most recent date of User login. This will support us in identifying Users that are not regularly accessing the system so that we can provide additional training as necessary, and it will also help us identify those that are regularly using the system as potential candidates for the role of Process Experts.