According to Federal Law (Bildungsdokumentationsgesetz § 9), all students of Austrian Universities are obliged to supply statistical data at the start of studies.
The data have to be entered by the students themselves, directly via the following web page of Statistik Austria:
www.statistik.at/uhstat/uhstat1/#
Data entry requires an Austrian Insurance Number (Sozialversicherungsnummer).
Persons without an Austrian Insurance Number will be issued a Substitute Code (Ersatzkennzeichen). The code will be sent by the university's study services within the process of enrolment at the university. In this case, data entry can be performed only after enrolment has been processed.
→ more info on procedure and direct submission of confirmation