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).
Gerardo is now well below its former popularity. All-time it's been given to 55,254 U.S. babies, the 1,098th most common name by sound today, peaking at 1,713 in 2000, with 401 in 2025.
Gerardo has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).