as per Gregory Clark (The Son Also Rises). Indian Christians merit a separate category (why? they are all Brahmins). Separate Iranian Muslim category (there must be a large count of Iranian non-muslim physicians). Chinese are surprisingly low down in the ranks. Black African is possibly the most meaningless classification (the author would probably like to single out black non-Americans, but then there is also black Haitian).
As far as Indians are concerned it would be of interest to look at data across generations- first generation, second generation,...and so on.