Among all the production technicians, how many have a below average pay rate for a production technician?
production technician is a job title; below average rate refers to Rate<AVG(Rate);
SELECT COUNT(T1.BusinessEntityID) FROM Employee AS T1 INNER JOIN EmployeePayHistory AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE T1.JobTitle LIKE 'Production Technician%' AND T2.Rate < ( SELECT AVG(T2.Rate) FROM Employee AS T1 INNER JOIN EmployeePayHistory AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE T1.JobTitle LIKE 'Production Technician%' )