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).
Dana is now well below its former popularity. All-time it's been given to 262,439 U.S. babies, the 1,414th most common name by sound today, peaking at 8,325 in 1971, with 297 in 2025.
By sound, Dana also includes the spellings Dayna, Danah.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).