Question: Find the average number of ornaments sold each month in 2018.
SQL: SELECT CAST(SUM(T2.`Order Quantity`) AS REAL) / 12 FROM Products AS T1 INNER JOIN `Sales Orders` AS T2 ON T2._ProductID = T1.ProductID WHERE T1.`Product Name` = 'Ornaments' AND T2.OrderDate LIKE '%/%/18'