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).
Aaron is down from its peak but still widely used. All-time it's been given to 994,125 U.S. babies, the 120th most common name by sound today, peaking at 30,536 in 1983, with 4,997 in 2025.
By sound, Aaron also includes the spellings Erin, Aron, Arron, Eryn, Arin, Erinn, Aryn.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).