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).
Kai
Kai has been climbing in recent years. All-time it's been given to 88,284 U.S. babies, the 117th most common name by sound today, peaking at 6,333 in 2022, with 4,351 in 2025.
By sound, Kai also includes the spellings Kye, Khai.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).