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).
Samuel was more common in the past and has since settled at a lower, steady level. All-time it's been given to 831,382 U.S. babies, the 43rd most common name by sound today, peaking at 14,984 in 2001, with 8,377 in 2025.
By sound, Samuel also includes the spellings Samual, Sammuel.