Don't know if anybody ever saw the little table on the link below. It shows the background of the Vors in the "Russian" underworld. It also features a link to a Vor database. Don't know how much of it is accurate nowadays though;

http://www.unz.com/akarlin/how-russian-is-the-russian-mafia/

The biggest Vor suppliers seem to be:

Georgians: a whopping 242 vors
Russians: 53 vors
Armenians: 30 vors
Yezidis (mostly from Georgia and Armenia): 26 vors - which is disproportionate seeing their community only numbers about 150000 in the former USSR
Azerbaijanis: 16 vors
Chechens: 9 vors
Abkhazians (though most of those seem to be of ethnic Georgian origin as well): 9 vors
Jews (often from Ukraine): 7 vors