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).
Ralph was more common in the past and has since settled at a lower, steady level. All-time it's been given to 415,858 U.S. babies, the 1,835th most common name by sound today, peaking at 8,902 in 1921, with 211 in 2025.
Ralph has no common alternate spellings by sound.