How much is the annual revenue of the customer with the most number of shipments?
customer with the most number of shipment refers to cust_id where Max(Count(ship_id))
SELECT T2.annual_revenue FROM shipment AS T1 INNER JOIN customer AS T2 ON T1.cust_id = T2.cust_id GROUP BY T1.cust_id ORDER BY COUNT(T1.cust_id) DESC LIMIT 1