How many shipments were shipped to customers living in California in year 2016?
living in California refers to state = 'CA'; in year 2016 refers to CAST(ship_date AS DATE) = 2016
SELECT COUNT(*) AS per FROM customer AS T1 INNER JOIN shipment AS T2 ON T1.cust_id = T2.cust_id WHERE STRFTIME('%Y', T2.ship_date) = '2016' AND T1.state = 'CA'