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).
Evan is down from its peak but still widely used. All-time it's been given to 292,426 U.S. babies, the 283rd most common name by sound today, peaking at 10,410 in 2007, with 2,462 in 2025.
Evan has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).