*** In 2017, 100,000 South Africans migrated to the United States. ***
Source, please. Stats I saw said between 1990-2017, 100,000 South Africans were living in the US.
You are correct.
As of 2017, there were 100,000 South Africans living in the United States.
http://www.pewglobal.org/2018/02/28/global-migrant-stocks/?country=ZA&date=2017