instruction: how much is the average cost for a hospital that contains demeclocycline until 2104?
response: SELECT AVG(t1.c1) FROM (SELECT SUM(cost.cost) AS c1 FROM cost WHERE cost.hadm_id IN (SELECT prescriptions.hadm_id FROM prescriptions WHERE prescriptions.drug = 'demeclocycline') AND STRFTIME('%y', cost.chargetime) <= '2104' GROUP BY cost.hadm_id) AS t1