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).
Edwin has stayed fairly steady in American naming for generations. All-time it's been given to 248,744 U.S. babies, the 758th most common name by sound today, peaking at 3,849 in 1922, with 798 in 2025.
Edwin has no common alternate spellings by sound.