CREATE TABLE table_66381 ("Club" TEXT, "Sport" TEXT, "Founded" FLOAT, "League" TEXT, "Venue" TEXT)

How many different dates are there for founded teams for the venue of champion window field?
SELECT COUNT("Founded") FROM table_66381 WHERE "Venue" = 'champion window field'
SELECT COUNT("Founded") FROM "table_66381" WHERE "Venue" = 'champion window field'