How to read the band →
Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Nancy
Nancy is now well below its former popularity. All-time it's been given to 1,017,163 U.S. babies, the 1,477th most common name by sound today, peaking at 32,759 in 1947, with 265 in 2025.
By sound, Nancy also includes the spellings Nanci, Nancie.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).