How to read the band →
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).
Brendan
Brendan is now well below its former popularity. All-time it's been given to 138,001 U.S. babies, the 1,300th most common name by sound today, peaking at 6,152 in 1999, with 286 in 2025.
By sound, Brendan also includes the spellings Brenden, Brendon.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).