CREATE TABLE table_204_823 (id DECIMAL, "dates" TEXT, "location" TEXT, "attendance" TEXT, "official guests" TEXT, "notes" TEXT)

how many times was the rosemont convention center used ?
SELECT COUNT(*) FROM table_204_823 WHERE "location" = 'rosemont convention center'
SELECT COUNT(*) FROM "table_204_823" WHERE "location" = 'rosemont convention center'