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 (area__in_km²_ INTEGER, markatal INTEGER)
### Question:
What is the average Area (in km²), when Markatal is less than 0?
### Answer:
SELECT AVG(area__in_km²_) FROM table_name_81 WHERE markatal < 0