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).
Warren
Warren has been climbing back after years of decline. All-time it's been given to 185,502 U.S. babies, the 562nd most common name by sound today, peaking at 7,826 in 1921, with 1,493 in 2025.
Warren has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).