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).
Adele has stayed fairly steady in American naming for generations. All-time it's been given to 58,130 U.S. babies, the 1,149th most common name by sound today, peaking at 1,360 in 1918, with 451 in 2025.
By sound, Adele also includes the spellings Adell, Adelle, Adel.