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).
Ernest is now well below its former popularity. All-time it's been given to 363,469 U.S. babies, the 1,634th most common name by sound today, peaking at 6,880 in 1924, with 238 in 2025.
By sound, Ernest also includes the spellings Earnest.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).