CREATE TABLE table_204_568 (id DECIMAL, "pennant" TEXT, "name" TEXT, "hull builder" TEXT, "ordered" TEXT, "laid down" TEXT, "launched" TEXT, "accepted into service" TEXT, "commissioned" TEXT, "est. building cost" TEXT, "fate" TEXT)

how many ships were laid down in september ?
SELECT COUNT(*) FROM table_204_568 WHERE "laid down" = 9
SELECT COUNT(*) FROM "table_204_568" WHERE "laid down" = 9