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).
Neil
Neil is now well below its former popularity. All-time it's been given to 163,951 U.S. babies, the 1,075th most common name by sound today, peaking at 3,059 in 1952, with 478 in 2025.
By sound, Neil also includes the spellings Neal, Neel.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).