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).
Evelyn is down from its peak but still widely used. All-time it's been given to 682,549 U.S. babies, the 21st most common name by sound today, peaking at 14,621 in 1921, with 10,571 in 2025.
By sound, Evelyn also includes the spellings Evelynn, Evalyn, Evelin, Evelyne, Evalynn. Spellings sometimes heard the same way: Eveline.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).