what week number was at memorial stadium?
CREATE TABLE table_35471 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Game site" text,
    "Attendance" real
)
SELECT AVG("Week") FROM table_35471 WHERE "Game site" = 'memorial stadium'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: what week number was at memorial stadium? ### Input: CREATE TABLE table_35471 (
    "Week" real,
    "Date" text,
    "Opponent" text,
    "Result" text,
    "Game site" text,
    "Attendance" real
) ### Response: SELECT AVG("Week") FROM table_35471 WHERE "Game site" = 'memorial stadium'