What exactly is the Active Espionage Mission "Spread Culture"? Does it increase the percentage of my civ's population in a foreign city, so it would sonner join my civ? Or does it change percentage of my influence on a tile that is under both mine and foreign influence, so it would sooner become under my control? Right now I have a spy in foreign territory, but on the Espionage Screen, the "Spread Culture" line is blank (no number) for all cities - even though the Spy is current at one of those cities (and has not been moved this turn). So under what condition does "Spred Culture" become available?