Table schema:
CREATE TABLE table_name_66 (off_site_atms INTEGER, bank_type VARCHAR, on_site_atms VARCHAR)

Question: With foreign banks as the bank type, and on-site ATMS less than 218, what is the average off-site ATMs?
SQL: SELECT AVG(off_site_atms) FROM table_name_66 WHERE bank_type = "foreign banks" AND on_site_atms < 218