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 (format VARCHAR, year VARCHAR, catalog_number VARCHAR)
### Question:
What format is after 1991 and has a Catalog Number of 81868?
### Answer:
SELECT format FROM table_name_64 WHERE year > 1991 AND catalog_number = "81868"