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).
Lennon
Lennon has been climbing in recent years. All-time it's been given to 20,579 U.S. babies, the 448th most common name by sound today, peaking at 1,730 in 2022, with 1,729 in 2025.
Lennon has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).