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).
Joseph has been easing down from its peak but is still widely used. All-time it's been given to 2,705,033 U.S. babies, the 63rd most common name by sound today, peaking at 33,135 in 1956, with 7,370 in 2025.
By sound, Joseph also includes the spellings Joesph, Josef.