Namewise

Close in one country, far apart in another

Within twenty places of each other on average in one registrar's list, and more than two hundred apart on average in another's.

841 pairs, drawn from the 2,573 names with a recorded popularity standing (common, familiar, uncommon). Every one comes from a single published list, where both names were measured on the same scale, in the same year, by the same registrar — so each is a fact about that ranking rather than a similarity judgement, and never a claim that one name displaced the other.