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).
Cheryl was a common American name in the 1950s but is rarely given today. It's been given to 535,720 U.S. babies all time and once ranked 141st by sound, peaking at 28,384 in 1958 (down to 45 in 2025).
By sound, Cheryl also includes the spellings Sheryl, Sherrill, Sherryl, Sherrell.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).