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).
Hadley has climbed over the years and is holding near its high. All-time it's been given to 58,416 U.S. babies, the 258th most common name by sound today, peaking at 3,664 in 2014, with 2,745 in 2025.
By sound, Hadley also includes the spellings Hadlee, Hadleigh.