Recorded in 4 decades
Names ranked in exactly 4 distinct decades, across every registrar together.
Not the same as the span between the first and last record: a name ranked in 1950 and again in 2020 and never between covers two decades, not eight. Counting decades rather than years is what separates a record that keeps reappearing from one long unbroken stretch — the run length dimension measures the second.
4,610 names, ordered by most decades first.