Number-One Song of the Year Quiz

Every song to finish a year at number one on Billboard's year-end chart, from 1946 to the present — the complete published run, one per year. Name each from its year (the artist is your clue on the easier tiers; on the hardest the rows are simply in chart order), pick the year's real number one from a group of genuine chart-toppers, match each song to the artist credited with it, sort a selection into the order they led, or tap the pop number ones out of a grid seeded with real R&B and country number ones. Parsed verbatim from the published year-end table; no answer is named here.