Database: sales
Question: Among all the customers who have purchased ML Bottom Bracket, identify the percentage of sales by Albert I. Ringer?
SQL: SELECT CAST(SUM(IIF(T3.FirstName = 'Albert' AND T3.MiddleInitial = 'I' AND T3.LastName = 'Ringer', 1, 0)) AS REAL) * 100 / COUNT(T2.CustomerID) FROM Products AS T1 INNER JOIN Sales AS T2 ON T1.ProductID = T2.ProductID INNER JOIN Employees AS T3 ON T2.SalesPersonID = T3.EmployeeID WHERE T1.Name = 'ML Bottom Bracket'