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).
Keith
Keith is now well below its former popularity. All-time it's been given to 440,123 U.S. babies, the 1,299th most common name by sound today, peaking at 12,483 in 1957, with 311 in 2025.
Keith has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).