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).
Finn
Finn climbed for decades and has been a steadily popular name ever since. All-time it's been given to 35,380 U.S. babies, the 400th most common name by sound today, peaking at 2,417 in 2017, with 1,717 in 2025.
Finn has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).