CREATE TABLE table_17327458_1 (manner_of_departure VARCHAR, date_of_vacancy VARCHAR)

How many vacancies happened on 25 May?
SELECT COUNT(manner_of_departure) FROM table_17327458_1 WHERE date_of_vacancy = "25 May"
SELECT COUNT("manner_of_departure") FROM "table_17327458_1" WHERE "25 May" = "date_of_vacancy"