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).
Fred
Fred was a common American name in the 1920s but is rarely given today. It's been given to 345,684 U.S. babies all time and once ranked 109th by sound, peaking at 6,566 in 1924 (down to 80 in 2025).
Fred has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).