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).
Gabrielle has been slowly declining from its former popularity. All-time it's been given to 142,547 U.S. babies, the 975th most common name by sound today, peaking at 6,318 in 1998, with 498 in 2025.
By sound, Gabrielle also includes the spellings Gabriele.