How to recreate the data counts in Administer Concurrent Managers (Running & Pending)?

Hello,

I need write a query that will return the number of concurrent requests running and pending for a given Manager.  The data is available on this form:  System Administrator > Concurrent > Manager > Administer > Administer Concurrent Managers.  I cannot find how the Form generates the counts.  I was able to find some of the details via Help > Diagnostics > Examine > Block = SYSTEM, Field = LAST_QUERY.  But it doesn't tell me where running and pending counts are stored or how they are generated.

I would like to see how many concurrent requests are running and pending so that I can write an alert to fire when the counts are above a certain threshold.  So, if the system is backing up I will get a notification.