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).
Amalia has stayed fairly steady in American naming for generations. All-time it's been given to 16,478 U.S. babies, the 1,004th most common name by sound today, peaking at 576 in 2023, with 530 in 2025.
Amalia has no common alternate spellings by sound.