Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_6 (founded INTEGER, club VARCHAR, capacity VARCHAR)
### Question:
How many foundeds have stade tunisien as the club, with a capacity greater than 18,000?
### Answer:
SELECT SUM(founded) FROM table_name_6 WHERE club = "stade tunisien" AND capacity > 18 OFFSET 000