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).
Micah has been climbing in recent years. All-time it's been given to 150,474 U.S. babies, the 152nd most common name by sound today, peaking at 4,641 in 2011, with 4,454 in 2025.
By sound, Micah also includes the spellings Mikah, Mica, Myka, Mykah, Micha. Spellings sometimes heard the same way: Mika.