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).
Allison
Allison is down from its peak but still widely used. All-time it's been given to 530,993 U.S. babies, the 166th most common name by sound today, peaking at 12,395 in 1994, with 4,159 in 2025.
By sound, Allison also includes the spellings Alison, Allyson, Alyson, Alisson.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).