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).
Vanessa has been slowly declining from its former popularity. All-time it's been given to 278,148 U.S. babies, the 689th most common name by sound today, peaking at 8,007 in 1985, with 841 in 2025.
By sound, Vanessa also includes the spellings Vanesa, Venessa, Vannessa.