What is the average number of inspections carried out in the year 2010 by a sanitarian whose salary is over 70000?
in the year 2010 refers to inspection_date like '2010%'; salary is over 70000 refers to salary > 70000; average number = divide(sum(inspection where inspection_date like '2010%'), sum(employee_id where salary > 70000))
SELECT CAST(SUM(CASE WHEN T2.inspection_date LIKE '2010%' THEN 1 ELSE 0 END) AS REAL) / SUM(CASE WHEN T1.salary > 70000 THEN 1 ELSE 0 END) FROM employee AS T1 INNER JOIN inspection AS T2 ON T1.employee_id = T2.employee_id