I don't need statistical data, but more personal one as I am conducting a family research. I looked everywhere online, but it seems this part has not been digitalized yet - no wonder having in mind the size of Austria-Hungary. The good thing is that my family comes from a small town/village in the Bács-Bodrog region (today's Serbia) and we have a very specific Hungarian surname. Any Hungarians here who could help me? I live in the US... A friend of mine tried in Serbia, but they told him that they don't have the census data from 1880, only 1982 onwards.
Statistik Austria has some data on the 1880 census ("Volkszählung").
Original sources could be found in the Austrian State Archives, altough I don't know if they also kept the material for the Hungarian half of the empire.
The k.k. Statistische Central-Commission had their own statistics magazine (Statistische Monatsschrift) that published the preliminary results in their 1881 edition. Fortunately, the Austrian National Library has public records of their entire collection here and specifically the 1880 census addendum here.
Just statistics though. I don't even know whether the census included surnames at all.