I'm sorry, but I'm too lazy to dig up those statistics for you. Part of the reason is that I consider your question to be fundamentally misdirected.
First, I'd like to point out that medical staff form just the tip of the iceberg in terms of wage-reduction by immigrants. For example, my father in law lives in an old age home staffed almost entirely with low-wage foreigners - a mix of immigrants, migrants, what-have you. There are job markets in health and old age care, cleaning, agriculture and construction that completely dwarf just that for doctors.
Secondly, because much of the current discussion of immigrants relates specifically to refugees: to selectively accept desirable highly-qualified refugees from countries people are fleeing for their lives would be deplorably, cynically selfish and inhumane.
Third, if I remember correctly, "nationals-only" reproduction in Germany and some other European countries, but also e.g. Japan is below the level required to sustain a population (there's a technical term for that, but I've forgotten it), so many modern countries actually _need_ immigrants to fill job vacancies in countries with industries that insist on continuing to grow regardless of populations.
The Japanese are (at the moment) resolved to let their country dwindle out before diluting their treasured racial stock. That's their decision, and they can go that way if they want to. Other countries, meanwhile, don't base their immigration policies on -let's be honest- racism, or less so.