In 1919, the area corresponded to the following parts of the Bulgarian "okrugs": Kyustendil, , Tzaribrod , Tran , Kula and Vidin . Bulgarian sources claim that the Bulgarian population made 98% of the population in Bosilegrad and 95% of the population in Tzaribrod at the time. In the Yugoslav census of 1931, all South Slavs were simply counted as Yugoslavs (Serbs, Croats, Slovenes, Bulgarians) so a comparison could not be made. According to the last Census in Serbia from 2002, Bulgarians made 50% and 71% of population in Dimitrovgrad and Bosilegrad respectively.