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 (tonnage INTEGER, name_of_ship VARCHAR)
### Question:
What is the average tonnage of the ship named proletarij?
### Answer:
SELECT AVG(tonnage) FROM table_name_81 WHERE name_of_ship = "proletarij"