CREATE TABLE table_30997 ("Episode" FLOAT, "Date" CLOB, "Official rating 4+" CLOB, "Share 4+" CLOB, "Official rating 16-39" CLOB, "Share 16-39" CLOB)

When did the official rating 4+ reach 4 633 925?
SELECT "Date" FROM table_30997 WHERE "Official rating 4+" = '4 633 925'
SELECT "Date" FROM "table_30997" WHERE "Official rating 4+" = '4 633 925'