CREATE TABLE table_73647 ("WEEK" FLOAT, "Sydney" FLOAT, "Melbourne" FLOAT, "Brisbane" FLOAT, "Adelaide" FLOAT, "Perth" FLOAT, "TOTAL" FLOAT, "WEEKLY RANK" FLOAT)

How many Adelaide viewers were there in Week 5?
SELECT "Adelaide" FROM table_73647 WHERE "WEEK" = '5'
SELECT "Adelaide" FROM "table_73647" WHERE "WEEK" = '5'