CREATE TABLE table_33315 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

What was the average size of the crowd for matches held at Corio Oval?
SELECT AVG("Crowd") FROM table_33315 WHERE "Venue" = 'corio oval'
SELECT AVG("Crowd") FROM "table_33315" WHERE "Venue" = 'corio oval'