Counter espionage

Hey, I have 2 questions regarding this action.

- What is the chance a counter espionage is succesfull? From my experience I would gess 30%.

- Does placing 2 counter espionage spies in the same province increase the chance of a succelfull counter espionage mission?

Having 20 sabotage spies in my country for 3 days now. They replenish just as quick as I catch them, so the last question is really important for me.