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).
Hailey has dropped sharply from its peak but is still widely used. All-time it's been given to 490,320 U.S. babies, the 174th most common name by sound today, peaking at 23,741 in 2000, with 3,615 in 2025.
By sound, Hailey also includes the spellings Haley, Hayley, Haylee, Hailee, Haleigh, Haylie, Halie, Hailie, Hayleigh, Haily, Halee. Spellings sometimes heard the same way: Hali, Halley.