There are ~700k h1bs out of ~157 million American jobs. So about 99.6% of jobs in America are held by Americans and 0.4% by h1bs.
People are also now learning this fact, which is why you’re getting unpalatable politicians elected.
Irony is, that doesn't prevent such sentiments as yours leading to people like Trump. I had a chance to live in the USA years back, I'm glad I didn't bother to take it.
Do you have numbers? If you don’t, the appropriate baseline is population.