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 manufacturer (Num_of_Factories INTEGER, num_of_shops INTEGER)
### Question:
Find the average number of factories for the manufacturers that have more than 20 shops.
### Answer:
SELECT AVG(Num_of_Factories) FROM manufacturer WHERE num_of_shops > 20