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).
Beau has been climbing in recent years. All-time it's been given to 82,452 U.S. babies, the 125th most common name by sound today, peaking at 5,952 in 2025, with 5,952 in 2025.
By sound, Beau also includes the spellings Bo.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).