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).
Roland has stayed fairly steady in American naming for generations. All-time it's been given to 115,343 U.S. babies, the 1,096th most common name by sound today, peaking at 2,148 in 1924, with 498 in 2025.
By sound, Roland also includes the spellings Rolland, Rowland.