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).
Knox
Knox has been climbing in recent years. All-time it's been given to 24,382 U.S. babies, the 422nd most common name by sound today, peaking at 1,931 in 2022, with 1,849 in 2025.
Knox has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).