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_31 (rank INTEGER, date VARCHAR, mark VARCHAR)
### Question:
What is the average rank of the record on 2007-06-21 with a mark less than 91.29?
### Answer:
SELECT AVG(rank) FROM table_name_31 WHERE date = "2007-06-21" AND mark < 91.29