Microsoft had a lot when I was at the HQ - certainly in the double digits. 20-30% I would guess. From all over but majority were Chinese and Indian. And Microsoft uses a ton of contractors that are non US citizens. But you literally had people from all over the world working side by side.
Microsoft is a little hard to tell given that one thing they do is help the non citizens become citizens.
When I left grad school, there were about 50 students in my department. Out of them, I can think of at least 8 non-citizens (two Russian, one French, one Turkish, one Indian, one Chinese, one Argentinian, and one Colombian), and I’ve got the feeling that I’m forgetting one or two. Prior students also included a few more Indians, a Pakistani, a South African, an Eritrean, and a Canadian. I’ve been to Fourth of July parties where Yankees were in the minority, and Thanksgiving dinners where I was the only one.
There were about the same number of professors, but almost all of them were citizens. There were one each from Australia, Japan, and the Netherlands, but I’m pretty sure all three of them were naturalized. There’s another who was from France who I think was still alien as of when I left.
I am a tech writer working with software developers who do major installs at various companies. Right now, the project I am on probably has about 25-30% non-citizens working on the project. The actual percent is probably lower as I’m not sure how many of those with accents are naturalized citizens. A number of the “foreigners” are actually 1st gen citizens, born here but but have Asian or South Asian ancestry and so they get mistaken for foreigners by the naive.
I have no idea.
I know that a few of my coworkers are not US citizens, and I know the birthplaces of a few others that are in the US, but the vast majority, I don’t know, it’s never come up?