The controller in counties of the third to eighth classes shall keep a register of all vouchers drawn and a copy of each voucher. When the check or checks drawn upon each voucher has been paid by the treasury the controller shall cancel the voucher or otherwise indicate the payment. The controller shall report to the commissioners monthly or oftener, if required by them, the amount of outstanding checks registered and the amount of money in the treasury or the amount of any particular unencumbered appropriation items involved.