How to read the band →
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).
Eileen
Eileen is now well below its former popularity. All-time it's been given to 207,860 U.S. babies, the 1,071st most common name by sound today, peaking at 4,680 in 1947, with 456 in 2025.
By sound, Eileen also includes the spellings Ilene. Spellings sometimes heard the same way: Aileen.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).