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_64 (year INTEGER, result VARCHAR, world_rank VARCHAR)
### Question:
What Year has a Result smaller than 20.31, and a World Rank of 5th?
### Answer:
SELECT AVG(year) FROM table_name_64 WHERE result < 20.31 AND world_rank = "5th"