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).
Howard was more common in the past and has since settled at a lower, steady level. All-time it's been given to 348,342 U.S. babies, the 1,716th most common name by sound today, peaking at 7,749 in 1921, with 226 in 2025.
Howard has no common alternate spellings by sound.