Database: books
Question: Among all addresses provided by customers, identify the percentage that are not in use anymore.
SQL: SELECT CAST(SUM(CASE WHEN T2.address_status = 'Inactive' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM customer_address AS T1 INNER JOIN address_status AS T2 ON T2.status_id = T1.status_id