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_81 (ends INTEGER, nat VARCHAR, transfer_window VARCHAR)
### Question:
What is the average end year of the player from swe and a summer transfer window?
### Answer:
SELECT AVG(ends) FROM table_name_81 WHERE nat = "swe" AND transfer_window = "summer"