Seeing a side discussion about Australian vs. UK immigration system, I grew curious as to how popular are different models of immigration systems around the world.
I'm looking for a good compiled data on how popular specific features are among the countries, including the following typical categories:
Limited vs. Unlimited (e.g. is the # of immigrants capped; and how large is it compared to present population)
Degree of selectivity (e.g. are people with needed skills prioritized generally or exclusively) (this one is harder to score/evaluate since for example USA has a hybrid system where some spots are reserved for skills based visas and some for no-requirements-based visas)