Why am I losing Manpower when it says I am gaining it?

Question

In one month my Manpower dropped from 10,191 to 9,204, but the hover says I am gaining 813 each month. All of my armies were fully replenished several months before when I had around 15k Manpower.

Am I misreading the hover information? Is there another screen that shows more details or what is causing the drop?

Update: I am above the force-limit (76/72), but the only penalty mentioned in the hover is a monetary cost of 1.43/month. Is this related?

Answer 1

The drain was caused by attrition. I never noticed this until now because my armies were always below the supply limit of the provinces they were in. You have to select each unit to see the attrition percentage.

I had one army with 38 regiments in a province with a 22 supply limit. Splitting the army and moving half to the neighboring province solved the problem.