Write SQL query to solve given problem: Find the average yearly order by customer Weimei Corp for 2018, 2019 and 2020.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.OrderNumber) / 3 FROM `Sales Orders` AS T1 INNER JOIN Customers AS T2 ON T2.CustomerID = T1._CustomerID WHERE (T1.OrderDate LIKE '%/%/18' AND T2.`Customer Names` = 'Weimei Corp') OR (T1.OrderDate LIKE '%/%/19' AND T2.`Customer Names` = 'Weimei Corp') OR (T1.OrderDate LIKE '%/%/20' AND T2.`Customer Names` = 'Weimei Corp')