CREATE TABLE table_203_653 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

the average silver medal count of the first five ranked nations ?
SELECT AVG("silver") FROM table_203_653 WHERE "rank" <= 5
SELECT AVG("silver") FROM "table_203_653" WHERE "rank" <= 5