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).
Colin
Colin is now well below its former popularity. All-time it's been given to 216,113 U.S. babies, the 449th most common name by sound today, peaking at 8,268 in 2004, with 1,569 in 2025.
By sound, Colin also includes the spellings Collin.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).