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).
Ashley was more common in the past and has since settled at a lower, steady level. All-time it's been given to 989,303 U.S. babies, the 342nd most common name by sound today, peaking at 61,135 in 1987, with 2,107 in 2025.
By sound, Ashley also includes the spellings Ashlee, Ashleigh, Ashly, Ashlie, Ashely, Ashli, Ashlea.