How to read the band →
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).
Otto
Otto has been climbing back after years of decline. All-time it's been given to 40,015 U.S. babies, the 581st most common name by sound today, peaking at 1,244 in 2024, with 1,241 in 2025.
Otto has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).