CREATE TABLE table_20536 ("#" FLOAT, "Air Date" TEXT, "Timeslot" TEXT, "Rating" TEXT, "Share" FLOAT, "18-49" TEXT, "Viewers" TEXT, "Weekly Rank" TEXT)

What broadcast dates have a weekly rank of 73?
SELECT COUNT("Air Date") FROM table_20536 WHERE "Weekly Rank" = '73'
SELECT COUNT("Air Date") FROM "table_20536" WHERE "Weekly Rank" = '73'