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).
Denver has been climbing in recent years. All-time it's been given to 23,413 U.S. babies, the 684th most common name by sound today, peaking at 995 in 2024, with 904 in 2025.
Denver has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).