Spying Question: Stealing Techs
I am not sure how stealing techs works. I have great spy%. I spied on several powers until I have reached Advanced knowledge on some races and High Espionage levels on one other. After I reached Advanced, I withdraw my active spies since the game says I don't need to do anything else. Rarely do I get any techs. Once I got it from the High race, but one of the Advanced races I got nothing from.
Does it depend on how many agents they have counterspying?
If I continue to put agents on their planets (even after Advanced knowledge) will it help me steal techs?
Thanks!