Tracking KPIs

I am looking for assistance viewing true stats within analytics for my agents.  I have several that show a large discrepancy between calls offered and calls answered.  Their RNA numbers are minimal but most calls are being categorized as UC Call.  Has anyone experienced this?  Does anyone know what UC Call is?  Are those calls just not being handled by any agent or are they requeuing?  

I would like to know how other FIs are properly tracking your monthly production in regards to calls offered vs answered.