user: Question: In how many different years was the warship that weights 1130 tons built?
Columns: ['Warship', 'tons ( L.ton )', 'Horse- power', 'Speed ( Knots )', 'Armour (Inch)', 'Main Artillery', 'Built Year']
Types: ['text', 'real', 'real', 'text', 'text', 'text', 'real']
Sample row: ['Cochrane', 3560.0, 2000.0, '9-12,8', 'up to 9', '6x9 Inch', 1874.0]
SQL:

assistant: SELECT COUNT("Built Year") FROM "Table" WHERE "tons ( L.ton )" = 1130.0;