In Croatia, Fois families are Croats (from Serbia ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Serbia.
Prevalence
About 10 people with faimily name Fois live in Croatia today, in three households only. There were 10 of them in the middle of the past century, and their number remains constant. They are located in one Croatian city only, in Zagreb (<10).
Outside Croatia
Family name Fois (including: Fays , Foys ) is present in 38 countries worldwide. "Foys " is used by some 50 people in the United States.