I am playing as Sweden and I have acquired Schleswig Holstein. There are 1 M of North Germans discriminated (level 3) constantly revolting. I supposed that this should have lowered their birth rate, slowly decreasing their population, but it is not happening (they have a whopping 4.4 birth rate for whatever reasonI). If it is impossible to replace them, how can I make them leave? Is migration controls enough or should I enact open borders?