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).
Jackson is down from its peak but still widely used. All-time it's been given to 490,343 U.S. babies, the 6th most common name by sound today, peaking at 26,076 in 2015, with 12,482 in 2025.
By sound, Jackson also includes the spellings Jaxon, Jaxson, Jaxen, Jaxxon.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).