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).
Pedro has stayed fairly steady in American naming for generations. All-time it's been given to 94,582 U.S. babies, the 823rd most common name by sound today, peaking at 1,711 in 2000, with 684 in 2025.
Pedro has no common alternate spellings by sound.