Database: retail_world
Question: Calculate the percentage salary of employees who handled orders shipped in 1996.
SQL: SELECT CAST(SUM(CASE WHEN STRFTIME('%Y', T2.ShippedDate) = '1996' THEN T1.Salary ELSE 0 END) AS REAL) * 100 / SUM(T1.Salary) FROM Employees AS T1 INNER JOIN Orders AS T2 ON T1.EmployeeID = T2.EmployeeID