user: Question: What was the gross tonnage of the ship that ended service in 1866?
Columns: ['Ships name', 'Entered service', 'Ended service', 'Gross Tonnage', 'Type of Vessel']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Avalon', '13 June 1864', '1866', 613.0, 'Paddle steamer']
SQL:

assistant: SELECT "Gross Tonnage" FROM "Table" WHERE "Ended service" = '1866';