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).
Terry is now well below its former popularity. All-time it's been given to 732,744 U.S. babies, the 1,583rd most common name by sound today, peaking at 31,807 in 1959, with 228 in 2025.
By sound, Terry also includes the spellings Terri, Teri, Terrie.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).