In Croatia, Dec families are Croats (from Zupanja area ). In the past century, relatively most of Croatian residents bearing this family name were born in Zupanja area and in Vinkovci. In Đurići in Zupanja area every sixtieth inhabitant had the family name Dec.
Prevalence
About 10 people with faimily name Dec live in Croatia today, in four households only. There were 10 of them in the middle of the past century, and their number remains constant. They are located in only four naselja i to in Djurici in Zupanja area (<10), Zupanja (<5), Zagreb (<5), and in Rijeka (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1932 in source Emigration Commission Zagreb.