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).
Jessica is now well below its former popularity. All-time it's been given to 1,064,996 U.S. babies, the 993rd most common name by sound today, peaking at 56,751 in 1987, with 436 in 2025.
By sound, Jessica also includes the spellings Jessika, Jesica.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).