CREATE TABLE table_24910733_2 (share VARCHAR2, air_date VARCHAR2)

How many share figures are there for the episode that aired on October 17, 2007?
SELECT COUNT(share) FROM table_24910733_2 WHERE air_date = "October 17, 2007"
SELECT COUNT("share") FROM "table_24910733_2" WHERE "October 17, 2007" = "air_date"