Great, so what is a good number? The US is currently at (possibly slightly above) the highest percentage of foreign born population in history, with projections that it will get much higher in our lifetimes. Mass immigration, legal or illegal has a huge effect on the culture of a country. The more selective you are, the better the quality of immigrant.

https://cis.org/Report/Immigrant-Workers-November-2022-19-Million-Over-2019