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).
Karen has been slowly declining from its former popularity. All-time it's been given to 1,083,582 U.S. babies, the 1,285th most common name by sound today, peaking at 42,855 in 1957, with 291 in 2025.
By sound, Karen also includes the spellings Karin, Karyn, Caryn, Caren, Karon, Keren, Karan, Carin, Caron.