Upload a GEDCOM file exported from Ancestry.com or FamilySearch and we'll match every given name against 65 years of U.S. Social Security data — surfacing names that were rare for their era, right at their all-time peak, decades ahead of the trend, or quietly making a comeback today.
From Ancestry: Tree Settings → Export Tree. From FamilySearch: Tree → Tree Search → Print/Export → GEDCOM. Both produce a .ged file.
No GEDCOM file? Type a list of ancestor first names — one per line, or separated by commas. Birth years aren't required, but the results are richer with a GEDCOM export since we can match names to their era.