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).
Colter
Colter has been climbing in recent years. All-time it's been given to 10,705 U.S. babies, the 499th most common name by sound today, peaking at 2,354 in 2025, with 2,354 in 2025.
Colter has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).