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).
Clayton has stayed fairly steady in American naming for generations. All-time it's been given to 142,969 U.S. babies, the 572nd most common name by sound today, peaking at 2,653 in 2000, with 1,219 in 2025.
By sound, Clayton also includes the spellings Klayton.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).