CREATE TABLE table_66858 ("Year" FLOAT, "Date" TEXT, "Title" TEXT, "Format ( s ) " TEXT, "Award description ( s ) " TEXT, "Result ( s ) " TEXT)

What is the average year with an award of platinum?
SELECT AVG("Year") FROM table_66858 WHERE "Award description(s)" = 'platinum'
SELECT AVG("Year") FROM "table_66858" WHERE "Award description(s)" = 'platinum'