CREATE TABLE table_64499 ("School" TEXT, "Location" TEXT, "Mascot" TEXT, "County" TEXT, "Year Joined" FLOAT, "Previous Conference" TEXT, "Year Left" FLOAT, "Conference Joined" TEXT)

Of all the schools that left before 2003, what is the average year joined?
SELECT AVG("Year Joined") FROM table_64499 WHERE "Year Left" < '2003'
SELECT AVG("Year Joined") FROM "table_64499" WHERE "Year Left" < '2003'