Generaly you dont get any one moving to your country unless your playing the US or some thing ells that has immigration coded into it..
You can only grow you pop if you have low taxes and so on, the lower the more it increases, and the reforms give it a bonus in pop growth seeing you dont loss most children or any other person due tothe form of deseases or illness, hánce the Health Reform, pops with in your nation will some times move around pending on jobs available, but no other group from any nation will move to your nation, thier wont be any french moving from france to Germany, dosnt work like that.
Make sure you taxes dont go to High, try to lower to a decent lvl normal around 50% for poor, around 30-40% for middle and upper class can generaly be high like around 60-70% if they decline in their numbers then lower the laxes for the specific group, also tarrifs also play a role in pop growth, every things a factor... also the low taxes and tarrif also mean you pop is less likely to move to anther country mostly to the America's..