Equifax, a credit rating agency, wants an estimate of the percentage of delinquent credit cards (where the customer has not made at least the minimum monthly payment by the due date). The manager randomly selects 175 credit card accounts and finds 7 are delinquent.

Equifax also wants an estimate of the percentage of delinquent credit cards with a balance owing of at least $5,000. They want the error on the estimate to be no more than 1.5% with 95% confidence. How many delinquent accounts would need to be sampled?