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).
Norma
Norma was a common American name in the 1930s but is rarely given today. It's been given to 279,349 U.S. babies all time and once ranked 260th by sound, peaking at 8,796 in 1931 (down to 95 in 2025).
Norma has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).