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_20 (year_built INTEGER, sub_parish__sogn_ VARCHAR)
### Question:
what is the year built of  kyrkjebø?
### Answer:
SELECT AVG(year_built) FROM table_name_20 WHERE sub_parish__sogn_ = "kyrkjebø"