Question: How much lower in percentage is the unit price of Ikura in order no. 10273 than its standard unit price?
SQL: SELECT CAST((T1.UnitPrice - T2.UnitPrice) AS REAL) * 100 / T1.UnitPrice FROM Products AS T1 INNER JOIN `Order Details` AS T2 ON T1.ProductID = T2.ProductID WHERE T2.OrderID = 10273 AND T1.ProductName = 'Ikura'