The name Nilsa has seen fluctuations over the decades, with peak years being 1957 (62 births) and 1960 (76 births). However, from the late 1980s onwards, there's a notable decline in popularity, with fewer than 15 births annually since 1993. In recent years, it seems Nilsa has become quite rare, with only 6-13 births per year between 2000 and 2022 (total of 1796 births overall).