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).
Phyllis
Phyllis was a common American name in the 1940s but is rarely given today. It's been given to 330,392 U.S. babies all time and once ranked 293rd by sound, peaking at 9,412 in 1947 (down to 7 in 2025).
By sound, Phyllis also includes the spellings Phillis, Phylis.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).