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).
Amy is now well below its former popularity. All-time it's been given to 779,895 U.S. babies, the 483rd most common name by sound today, peaking at 35,300 in 1975, with 1,363 in 2025.
By sound, Amy also includes the spellings Aimee, Amie. Spellings sometimes heard the same way: Ami.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).