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).
Gunner has been slowly declining from its former popularity. All-time it's been given to 41,686 U.S. babies, the 607th most common name by sound today, peaking at 2,427 in 2015, with 1,059 in 2025.
By sound, Gunner also includes the spellings Gunnar.