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).
Piper
Piper is now well below its former popularity. All-time it's been given to 66,241 U.S. babies, the 364th most common name by sound today, peaking at 4,394 in 2015, with 1,999 in 2025.
By sound, Piper also includes the spellings Pyper.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).